pelican (n.) Look up pelican at Dictionary.com
Old English pellicane, from Late Latin pelecanus, from Greek pelekan "pelican" (so used by Aristotle), apparently related to pelekas "woodpecker" and pelekys "ax," perhaps so called from the shape of the bird's bill. Spelling influenced in Middle English by Old French pelican. Used in Septuagint to translate Hebrew qaath. The fancy that it feeds its young on its own blood is an Egyptian tradition properly belonging to some other bird. Louisiana has been known as the Pelican state at least since 1859.
pell (n.) Look up pell at Dictionary.com
"a parchment," mid-15c., earlier "skin, hide" (mid-14c.), from Anglo-French pell, Old French pel "skin" (13c., Modern French peau), from Latin pellem, pellis "skin, leather, parchment, hide" (see film (n.)).
pell-mell (adv.) Look up pell-mell at Dictionary.com
"confusedly," 1570s, from Middle French pêle-mêle, from Old French pesle mesle (12c.), apparently a jingling rhyme on the second element, which is from the stem of the verb mesler "to mix, mingle" (see meddle). Phonetic French form pelly melly is attested in English from mid-15c.
pellagra (n.) Look up pellagra at Dictionary.com
chronic disease caused by dietary deficiency and characterized by skin eruptions, 1811, a hybrid formed from Latin pellis "skin" (see film (n.)) + Greek agra "a catching, seizure," related to agrein "to take, seize." But OED suggests it might be originally Italian pelle agra "rough skin." Related: Pellagrous.
pellet (n.) Look up pellet at Dictionary.com
mid-14c., from Old French pelote "small ball" (11c.), from Vulgar Latin *pilotta, diminutive of Latin pila "ball, playing ball, the game of ball," perhaps originally "ball of hair," from pilus "hair" (see pile (n.3)).
pellet (v.) Look up pellet at Dictionary.com
"to form into pellets," 1590s, from pellet (n.).
pellicle (n.) Look up pellicle at Dictionary.com
1540s, from Middle French pellicle (Modern French pellicule), from Latin pellicula "small or thin skin," diminutive of pellis "skin, leather, parchment, hide" (see film (n.)). Related: Pellicular.
pellucid (adj.) Look up pellucid at Dictionary.com
"transparent, translucent," 1610s, from Latin pellucidus "transparent," from pellucere "shine through," from per- "through" (see per) + lucere "to shine" (see light (n.)). Related: Pellucidly; pellucidity.
Peloponnesus (n.) Look up Peloponnesus at Dictionary.com
peninsula of southern Greece, late 15c., from Latin, from Greek Peloponnesos, second element apparently nesos "island" (see Chersonese); first element said to be named for Pelops, son of Tantalus, who killed him and served him to the gods as food (they later restored him to life). The proper name is probably from pellos "dark" + ops "face, eye." But the association with the peninsula name likely is folk etymology. Related: Peloponnesian.
peloton (n.) Look up peloton at Dictionary.com
1706, "small body of soldiers, platoon," from French peleton, derivative of pelote "ball, heap, platoon" (11c.); see platoon.
pelt (v.) Look up pelt at Dictionary.com
"to strike" (with something), c. 1500, of unknown origin; perhaps from early 13c. pelten "to strike," variant of pilten "to thrust, strike," from an unrecorded Old English *pyltan, from Medieval Latin *pultiare, from Latin pultare "to beat, knock, strike." Or from Old French peloter "to strike with a ball," from pelote "ball" (see pellet (n.)) [Klein]. Watkins says the source is Latin pellere "to push, drive, strike." Related: Pelted; pelting.
pelt (n.) Look up pelt at Dictionary.com
"skin of a fur-bearing animal," early 15c., of uncertain origin, perhaps a contraction of pelet (late 13c. in Anglo-Latin), from Old French pelete "fine skin, membrane," diminutive of pel "skin," from Latin pellis "skin, hide" (see film (n.)). Or perhaps the source of the English word is Anglo-French pelterie, Old French peletrie "fur skins," from Old French peletier "furrier," from pel.
pelvic (adj.) Look up pelvic at Dictionary.com
1830, irregularly formed from pelvis + -ic. OED prefers "the better-formed" French pelvien.
pelvis (n.) Look up pelvis at Dictionary.com
1610s, "basin-like cavity formed by the bones of the pelvic girdle," from Modern Latin, from Latin pelvis "basin, laver," Old Latin peluis "basin," from PIE *pel- "container" (cognates: Sanskrit palavi "vessel," Greek pelex "helmet," pelike "goblet, bowl," Old Norse and Old English full "cup").
pemmican (n.) Look up pemmican at Dictionary.com
1791, from Cree (Algonquian) /pimihka:n/ from /pimihke:w/ "he makes grease," from pimiy "grease, fat." Lean meat, dried, pounded and mixed with congealed fat and ground berries and formed into cakes used on long journeys. Also used figuratively for "extremely condensed thought or matter."
pen (n.1) Look up pen at Dictionary.com
"writing implement," late 13c., from Old French pene "quill pen; feather" (12c.) and directly from Latin penna "a feather, plume," in plural "a wing," in Late Latin, "a pen for writing," from Old Latin petna, pesna, from PIE *pet-na-, suffixed form of root *pet- "to rush; to fly" (see petition (n.)).

Latin penna and pinna "a feather, plume;" in plural "a wing;" also "a pinnacle; battlement" (see pin (n.)) are treated as identical in Watkins, etc., but regarded as separate (but confused) Latin words by Tucker and others, who derive pinna from PIE *spei- "sharp point" (see spike (n.1)) and see the "feather/wing" sense as secondary.

In later French, this word means only "long feather of a bird," while the equivalent of English plume is used for "writing implement," the senses of the two words thus are reversed from the situation in English. Pen-and-ink (adj.) is attested from 1670s. Pen name is recorded from mid-19c.
pen (n.2) Look up pen at Dictionary.com
"enclosure for animals," Old English penn, penne, "enclosure, pen, fold," of uncertain origin, perhaps related to Old English pinn "pin, peg" (see pin (n.)) on notion of a bolted gate or else "structure made of pointed stakes."
pen (v.1) Look up pen at Dictionary.com
late 15c., from pen (n.). Related: Penned; penning.
pen (v.2) Look up pen at Dictionary.com
"to enclose in a pen," c. 1200, from Old English *pennian, from the source of pen (n.2). Related: Penned; penning.
pen (n.3) Look up pen at Dictionary.com
slang, "prison," 1884, shortening of penitentiary; earlier use (1845) probably is a figurative extension of pen (n.2).
pen- Look up pen- at Dictionary.com
Brythonic for "head;" common in place names in Cornwall and Wales (such as Penzance, see also Pendragon).
pen-pal (n.) Look up pen-pal at Dictionary.com
also pen pal, 1931, from pen (n.1) + pal (n.). gradually replacing earlier pen-friend (1919).
penal (adj.) Look up penal at Dictionary.com
"pertaining to punishment," mid-15c., from Old French peinal (12c., Modern French pénal) and directly from Medieval Latin penalis, from Latin poenalis "pertaining to punishment," from poena "punishment," from Greek poine "blood-money, fine, penalty, punishment," from PIE *kwoina, from root *kwei- "to pay, atone, compensate" (cognates: Greek time "price, worth, honor, esteem, respect," tinein "to pay a price, punish, take vengeance;" Sanskrit cinoti "observes, notes;" Avestan kaena "punishment, vengeance;" Old Church Slavonic cena "honor, price;" Lithuanian kaina "value, price").
penalise (v.) Look up penalise at Dictionary.com
chiefly British English spelling of penalize; for suffix, see -ize. Related: Penalised; penalising.
penalize (v.) Look up penalize at Dictionary.com
1868, from penal + -ize. Related: Penalized; penalizing.
penalty (n.) Look up penalty at Dictionary.com
mid-15c., from Middle French penalité and directly from Medieval Latin poenalitatem (nominative poenalitas), from Latin poenalis (see penal). The sporting sense is first recorded 1885. Ice hockey penalty box attested by 1931.
penance (n.) Look up penance at Dictionary.com
late 13c., "religious discipline or self-mortification as a token of repentance and as atonement for some sin," from Anglo-French penaunce, Old French peneance (12c.), from Latin pænitentia (see penitence). Transferred sense is recorded from c. 1300.
penates (n.) Look up penates at Dictionary.com
Roman household gods, 1510s, from Latin penates "gods of the inside of the house," related to penatus "sanctuary of a temple" (especially that of Vesta), cognate with penitus "within" (see penetrate).
pence (n.) Look up pence at Dictionary.com
late 14c., contraction of penies, collective plural of penny. Spelling with -ce reflects the voiceless pronunciation.
penchant (n.) Look up penchant at Dictionary.com
1670s, from French penchant, noun use of present participle of Old French pencher "to incline," from Vulgar Latin *pendicare, a frequentative formed from Latin pendere "to hang" (see pendant (n.)).
pencil (n.) Look up pencil at Dictionary.com
early 14c., "an artist's fine brush of camel hair," from Old French pincel "artist's paintbrush" (13c., Modern French pinceau), from Latin penicillus "painter's brush, hair-pencil," literally "little tail," diminutive of peniculus "brush," itself a diminutive of penis "tail" (see penis). Small brushes formerly were used for writing before modern lead or chalk pencils; meaning "graphite writing implement" apparently evolved late 16c. Derogatory slang pencil-pusher "office worker" is from 1881; pencil neck "weak person" first recorded 1973.
pencil (v.) Look up pencil at Dictionary.com
1530s, "to mark or sketch with a pencil-brush," from pencil (n.). In reference to lead pencils from 1760s. Related: Penciled; penciling. To pencil (something) in "arrange tentatively" is attested from 1942.
pend (v.) Look up pend at Dictionary.com
c. 1500, "to depend, to hang," from French pendre, from Late Latin pendere "to hang" (see pendant). In some cases short for depend.
pendant (n.) Look up pendant at Dictionary.com
early 14c., "loose, hanging part of anything," from Anglo-French pendaunt "hanging" (c. 1300), Old French pendant (13c.), noun use of present participle of pendre "to hang," from Latin pendere "to hang," from PIE *(s)pend-, extended form of root *(s)pen- "to pull, draw, stretch" (see span (v.)). Meaning "dangling part of an earring" is attested from 1550s. Nautical sense of "tapering flag" is recorded from late 15c. "In this sense presumably a corruption of pennon" [OED].
pendency (n.) Look up pendency at Dictionary.com
1630s, from pendent + -cy.
pendent (adj.) Look up pendent at Dictionary.com
c. 1600 respelling of Middle English pendaunt "hanging, overhanging" (late 14c., from Old French pendant; see pendant) on model of its Latin original, pendentem.
pendentive (n.) Look up pendentive at Dictionary.com
1727, from French pendentif (mid-16c.), from Latin pendentem (nominative pendens) "hanging," present participle of pendere "to hang" (see pendent (adj.)).
pending (prep.) Look up pending at Dictionary.com
1640s, "during, in the process of," preposition formed from root of French pendant "during," literally "hanging," present participle of pendere "to hang, to suspend" (see pendant). Meaning patterned on a secondary sense of Latin pendente "not decided," literally "hanging," in legal phrase pendente lite "while the suit is pending." Use of the present participle before nouns caused it to be regarded as a preposition. As an adjective from 1797.
pendragon (n.) Look up pendragon at Dictionary.com
"Welsh warlord" (mainly known now in Arthurian Uther Pendragon), late 15c., title of a chief leader in war of ancient Britain or Wales, from pen "head" (see pen-) + dragon, which figured on the standard of a cohort.
pendular (adj.) Look up pendular at Dictionary.com
1734, from French pendulaire, from pendule, from pendre (see pendant).
pendulous (adj.) Look up pendulous at Dictionary.com
c. 1600, from Latin pendulus "hanging down," figuratively "doubtful, uncertain, hesitating," from pendere "to hang" (see pendant) + -ous. Related: Pendulously; pendulousness.
pendulum (n.) Look up pendulum at Dictionary.com
1660, from Modern Latin pendulum (1643), noun use of neuter of Latin adjective pendulus "hanging down," from pendere "to hang" (see pendant). The Modern Latin word is perhaps a Latinization of Italian pendolo.
Penelope Look up Penelope at Dictionary.com
fem. proper name, name of the faithful wife in the "Odyssey," from Greek Penelopeia, probably related to pene "thread on the bobbin," from penos "web," cognate with Latin pannus "cloth garment" (see pane (n.)). Used in English as the type of the virtuous wife (1580) as it was in Latin.
penetrable (adj.) Look up penetrable at Dictionary.com
early 15c., "penetrating," from Latin penetrabilis "penetrable, vulnerable," from penetrare (see penetrate). Meaning "capable of being penetrated" is attested from 1530s; figurative use by 1590s. Related: Penetrability.
penetrate (v.) Look up penetrate at Dictionary.com
1520s, from Latin penetratus, past participle of penetrare "to put or get into, enter into," related to penitus "within, inmost," penus "innermost part of a temple, store of food," penates "household gods." Related: Penetrated; penetrating.
penetrating (adj.) Look up penetrating at Dictionary.com
"touching the feelings intensely," 1630s, figurative present participle adjective from penetrate (v.).
penetration (n.) Look up penetration at Dictionary.com
c. 1600, "insight, shrewdness," from Latin penetrationem (nominative penetratio) "a penetrating or piercing," noun of action from past participle stem of penetrare (see penetrate). The sexual sense is attested from 1610s.
penguin (n.) Look up penguin at Dictionary.com
1570s, originally used of the great auk of Newfoundland (now extinct), shift in meaning to the Antarctic bird (which looks something like it, found by Drake in Magellan's Straits in 1578) is from 1580s. Of unknown origin, though often asserted to be from Welsh pen "head" (see pen-) + gwyn "white" (see Gwendolyn), but Barnhart says the proposed formation is not proper Welsh. The great auk had a large white patch between its bill and eye. The French and Breton versions of the word ultimately are from English.
penholder (n.) Look up penholder at Dictionary.com
1815, from pen (n.1) + holder.
penicillin (n.) Look up penicillin at Dictionary.com
1929, coined in English by Alexander Fleming (1881-1955), who first recognized its antibiotic properties, from Modern Latin Penicillium notatum (1867), the name of the mould from which it was first obtained, from Latin penicillus "paintbrush" (see pencil (n.)), in reference to the shape of the mould cells.