Online Etymology Dictionary

pack (v.): c.1300, "to put together in a pack," from pack (n.), possibly influenced by Anglo-French empaker (late 13c.) and Medieval Latin paccare "pack."

Some senses suggesting "make secret arrangement" are from an Elizabethan mispronunciation of pact. Sense of "to carry or convey in a pack" (1805) led to general sense of "to carry in any manner;" hence to pack heat "carry a gun," underworld slang from 1940s; "to be capable of delivering" (a punch, etc.), from 1921. Related: Packed; packing.
pack-horse (n.): late 15c., from pack (n.) + horse (n.).
pack-rat (n.): common name for the North American bushytailed woodrat (Neotoma cinerea) 1885, from pack (v.); so called from the rodents' habit of dragging objects off to their holes. Used figuratively or allusively from c.1850 of persons who won't discard anything, which means either the rat's name is older than the record or the human sense is the original one.
package (n.): 1530s, "the act of packing," from pack (n.) + -age; or from cognate Dutch pakkage "baggage." The main modern sense of "bundle, parcel" is first attested 1722. Package deal is from 1952.
package (v.): 1915, from package (n.). Related: Packaged; packaging.
packer (n.): mid-14c. (mid-13c. as a surname), agent noun from pack (v.).
packet (n.): mid-15c., from Middle English pak "bundle" (see pack (n.)) + diminutive suffix -et; perhaps modeled on Anglo-French pacquet (Middle French pacquet), which ultimately is a diminutive of Middle Dutch pak. A packet boat (1640s) originally was one that carried mails. Packet-switching attested from 1971.
packsaddle (n.): also pack-saddle, "saddle for supporting packs on the back of a mount," late 14c., pakke sadil; from pack (n.) + saddle (n.).
pact (n.): early 15c., from Old French pacte "agreement, treaty, compact" (14c.), from Latin pactum "agreement, contract, covenant," noun use of neuter past participle of pacisci "to covenant, to agree, make a treaty," from PIE root *pag- "fix, join together, unite, make firm" (cf. Sanskrit pasa- "cord, rope," Avestan pas- "to fetter," Greek pegnynai "to fix, make firm, fast or solid," Latin pangere "to fix, to fasten," Slavonic paž "wooden partition," Old English fegan "to join," fon "to catch seize").
pad (n.): 1550s, "bundle of straw to lie on," possibly from or related to Low German or obsolete Flemish pad "sole of the foot," which is perhaps from PIE *pent- "to tread, go" (see find (v.)), but cf. path (n.). Meaning "cushion-like part of an animal foot" is from 1790 in English. Generalized sense of "something soft" is from c.1700; the sense of "a number of sheets fastened together" (in writing pad, drawing pad, etc.) is from 1865.

Sense of "takeoff or landing place for a helicopter" is from 1960. The word persisted in underworld slang from early 18c. in the sense "sleeping place," and was popularized again c.1959, originally in beatnik speech (later hippie slang) in its original English sense of "place to sleep temporarily."
pad (v.2): "to stuff, increase the amount of," 1827, from pad (n.); transferred to expense accounts, etc. from 1913. Related: Padded; padding. Notion of a padded cell in an asylum or prison is from 1862 (padded room).
pad (v.1): "to walk," 1550s, probably from Middle Dutch paden "walk along a path, make a path," from pad, pat "path." Originally criminals' slang, perhaps of imitative origin (sound of feet trudging on a dirt road). Related: Padded; padding.
padding (n.): "material used in stuffing," 1828, verbal noun from pad (v.2).
paddle (n.): c.1400, padell "small spade," from Medieval Latin padela, of uncertain origin, perhaps from Latin patella "small pan, little dish, plate," diminutive of patina (see pan (n.)).

Meaning "short oar with a wide blade" is from 1620s. As an instrument used for beating clothes (and slaves, and schoolboys), it is recorded from 1828, American English. Paddle-ball attested from 1935.
paddle (v.1): "to dabble, wade in water," 1520s, probably cognate with Low German paddeln "tramp about," frequentative of padjen "to tramp, to run in short steps," from pad (v.). Related: Paddled; paddling. Meaning "to move in water by means of paddles" is a different word (see paddle (v.3)).
paddle (v.2): "to beat with a paddle, spank," 1856, from paddle (n.). Related: Paddled; paddling.
paddle (v.3): "to move in water by means of paddles," 1670s, from paddle (n.). To paddle one's (own) canoe "do for oneself" is from 1828.
paddle-wheel (n.): also paddlewheel, 1805, from paddle (n.) + wheel (n.).
paddock (n.1): "a frog, a toad," c.1300, diminutive of pad "toad," from Old Norse padda; common Germanic (cf. Swedish padda, Danish padde, Old Frisian and Middle Dutch padde "frog, toad," also Dutch schildpad "tortoise"), of unknown origin and with no certain cognates outside Germanic.
paddock (n.2): "an enclosure," 1620s, alteration of Middle English parrock, from Old English pearroc "enclosed space, fence" (see park (n.)). Or possibly from Medieval Latin parricus (8c.), which ultimately is from Germanic.
paddy (n.1): "rice field," 1620s, "rice plant," from Malay padi "rice in the straw." Main modern meaning "ground where rice is growing" (1948) is a shortening of paddy field.
Paddy (n.2): "Irishman," 1780, slang, from the pet form of the common Irish proper name Patrick (Irish Padraig). It was in use in black slang by 1946 for any "white person." Paddy wagon is 1930, perhaps so called because many police officers were Irish. Paddywhack (1881) originally meant "an Irishman."
padlock (n.): "removable lock," late 15c., from lokke (see lock (n.)), but the first element is of unknown origin.
padlock (v.): 1640s, from padlock (n.). Related: Padlocked; padlocking.
padre (n.): "priest, chaplain," 1580s, from Italian, Spanish, or Portuguese padre, from Latin patrem (nominative pater) "father" (see father (n.)). The title of the regular clergy in those languages. Papar was the name the Norse gave to Irish monks whom they found in Iceland when they arrived.
Padua: Italian city, Italian Padova, from Latin Patavium, probably from Gaulish *padi "pine," in reference to the pine forests thereabouts. Related: Paduan.
paean (n.): 1590s, from Latin paean "hymn of deliverance," from Greek paian "hymn, chant, hymn to Apollo," from Paian, a name of the god of healing; originally the physician of the gods (in Homer), later merged with Apollo; literally "one who touches" (i.e. "one who heals by a touch"), from paio "to touch, strike."
paederasty (n.): see pederasty.
paediatric (adj.): see pediatric.
paediatrician (n.): see pediatrician; also cf. pedo-.
paediatrics (n.): see pediatrics.
paedo-: see pedo-.
paedophile (n.): see pedophile; also cf. pedo-.
paedophilia (n.): see pedophilia; also cf. pedo-.
paella (n.): 1892, from Catalan paella, from Old French paele "cooking or frying pan" (Modern French poêle), from Latin patella "pan, dish" (see pail). So called for the pan in which it is cooked.
paeon (n.): metrical foot of one long and three short syllables (in any order), c.1600, from Latin paeon, from Greek paion (see paean). Related: Paeonic.
paesan (n.): 1930s, "fellow countryman, native of one's own country," from Italian dialect, from Late Latin pagensis "peasant, rustic" (see peasant). Spanish form paisano attested in English (New Mexico) from 1844.
pagan (n.): late 14c., from Late Latin paganus "pagan," in classical Latin "villager, rustic; civilian, non-combatant" noun use of adjective meaning "of the country, of a village," from pagus "country people; province, rural district," originally "district limited by markers," thus related to pangere "to fix, fasten," from PIE root *pag- "to fix" (see pact). As an adjective from early 15c.

Religious sense is often said to derive from conservative rural adherence to the old gods after the Christianization of Roman towns and cities; but the word in this sense predates that period in Church history, and it is more likely derived from the use of paganus in Roman military jargon for "civilian, incompetent soldier," which Christians (Tertullian, c.202; Augustine) picked up with the military imagery of the early Church (e.g. milites "soldier of Christ," etc.). Applied to modern pantheists and nature-worshippers from 1908.
paganism (n.): early 15c., from Church Latin paganismus, from paganus (see pagan).
page (n.1): "sheet of paper," 1580s, from Middle French page, from Old French pagene "page, text" (12c.), from Latin pagina "page, leaf of paper, strip of papyrus fastened to others," related to pagella "small page," from pangere "to fasten," from PIE root *pag- "to fix" (see pact).

Earlier pagne (12c.), directly from Old French. Usually said to be from the notion of individual sheets of paper "fastened" into a book. Ayto and Watkins offer an alternative theory: vines fastened by stakes and formed into a trellis, which led to sense of "columns of writing on a scroll." When books replaced scrolls, the word continued to be used. Related: Paginal. Page-turner "book that one can't put down" is from 1974.
page (n.2): "youth, lad, boy of the lower orders," c.1300, originally also "youth preparing to be a knight," from Old French page "a youth, page, servant" (13c.), possibly via Italian paggio (Barnhart), from Medieval Latin pagius "servant," perhaps ultimately from Greek paidion "boy, lad," diminutive of pais (genitive paidos) "child."

But OED considers this unlikely and points instead to Littré's suggestion of a source in Latin pagus "countryside," in sense of "boy from the rural regions" (see pagan). Meaning "youth employed as a personal attendant to a person of rank" is first recorded mid-15c.; this was transferred from late 18c. to boys who did personal errands in hotels, clubs, etc., also in U.S. legislatures.
page (v.1): "to summon or call by name," 1904, from page (n.2), on the notion of "to send a page after" someone. Related: Paged; paging.
page (v.2): "to turn pages," 1620s, from page (n.1). Related: Paged; paging.
pageant (n.): late 14c., "play in a cycle of mystery plays," from Medieval Latin pagina, of uncertain origin, perhaps from Latin pagina "page of a book" (see page (n.1)) on notion of "manuscript" of a play.

But an early sense in Middle English also was "stage or scene of a play" (late 14c.) and Klein says a sense of Latin pagina was "moveable scaffold" (probably from the etymological sense of "stake"). With excrescent -t as in ancient (adj.). Generalized sense of "showy parade, spectacle" is first attested 1805, though this notion is found in pageantry (1650s).
pageantry (n.): "splendid display," 1650s; see pageant + -ry.
pager (n.): "device that emits a signal when activated by a telephone call," 1968, agent noun from page (v.1).
paginate (v.): "to mark or number the pages of a publication," 1858 (implied in paginated), back-formation from pagination. Medieval Latin had paginare, but it had another sense. Related: Paginating.
pagination (n.): "action of marking page numbers," 1841, probably from French pagination (1835), from Latin pagina (see page (n.1)).
pagoda (n.): 1580s, pagode (modern form from 1630s), from Portuguese pagode (early 16c.), perhaps from a corruption of Persian butkada, from but "idol" + kada "dwelling." Or perhaps from or influenced by Tamil pagavadi "house belonging to a deity," from Sanskrit bhagavati "goddess," fem. of bhagavat "blessed, adorable," from *bhagah "good fortune," from PIE root *bhag- "to share out, apportion" (cf. Greek phagein "to eat;" see -phagous).
Pahlavi (n.): 1773, Iranian language spoken in Persia 3c.-10c., from Persian Pahlavi, from Old Persian Parthava "Parthia" (see Parthian).