ultrasonography (n.) Look up ultrasonography at Dictionary.com
1960, from ultrasonic + -graphy.
ultrasound (adj.) Look up ultrasound at Dictionary.com
1911, from ultra- "beyond" + sound (n.1). Compare ultrasonic. In reference to ultrasonic techniques of detection or diagnosis it is recorded from 1958.
ultraviolet (adj.) Look up ultraviolet at Dictionary.com
"beyond the violet end of the visible spectrum," 1840, from ultra- "beyond" + violet. Ultra-red (1870) was a former name for what now is called infra-red.
ululate (v.) Look up ululate at Dictionary.com
1620s, back-formation from ululation, or else from Latin ululatus, past participle of ululare. Related: Ululated; ululating.
ululation (n.) Look up ululation at Dictionary.com
1590s, from Latin ululationem (nominative ululatio) "a howling or wailing," noun of action from past participle stem of ululare "to howl, yell, shriek, wail, lament loudly," from a reduplicated imitative root (source also of Greek ololyzein "to cry aloud," Sanskrit ululih "a howling," Lithuanian uluti "howl," Gaelic uileliugh "wail of lamentation," Old English ule "owl").
Ulysses Look up Ulysses at Dictionary.com
Latin name for Odysseus, from Latin Ulysses, Ulixes. Famous for wandering as well as craftiness and ability at deceit. For -d- to -l- alteration, see lachrymose.
um Look up um at Dictionary.com
a sound denoting hesitation, 1670s.
Umayyad Look up Umayyad at Dictionary.com
member of a Muslim dynasty which ruled the Caliphate 661-750 C.E. and in 756 C.E. founded an emirate in Spain, 1758, from Arabic, from Umayya, proper name of an ancestor of Muhammad from whom the dynasty claimed descent.
umbel (n.) Look up umbel at Dictionary.com
1590s in botany, from Latin umbella "parasol, sunshade," diminutive of umbra "shade, shadow" (see umbrage).
umber (n.) Look up umber at Dictionary.com
brown earthy pigment, 1560s, from Middle French ombre (in terre d'ombre), or Italian ombra (in terra di ombra), both from Latin umbra "shade, shadow" (see umbrage) or else from Umbra, fem. of Umber "belonging to Umbria," region in central Italy from which the coloring matter first came (compare Sienna). Burnt umber, specially prepared and redder in color, is attested from c. 1650, distinguished from raw umber.
umbilical (adj.) Look up umbilical at Dictionary.com
"pertaining to the navel," 1540s, from Medieval Latin umbilicalis "of the navel," from Latin umbilicus "navel" (see umbilicus). Umbilical cord attested by 1753 (the native term is navel string).
umbilicus (n.) Look up umbilicus at Dictionary.com
"navel," 1610s, from Latin umbilicus "the navel," also "the center" of anything, from PIE *ombh-alo-, suffixed variant form of root *(o)nobh- "navel" (see navel). In English, mostly confined to medical writing. Latin umbilicus is source of Spanish ombligo as well as Old French lombril, literally "the navel," from l'ombril, which by dissimilation became Modern French nombril (12c.).
umbles (n.) Look up umbles at Dictionary.com
"edible inner parts of a deer or other animal," c. 1400, see humble.
umbo (n.) Look up umbo at Dictionary.com
"boss of a shield," 1921, from Latin umbo "shield-boss, knob, projection."
umbra (n.) Look up umbra at Dictionary.com
1590s, "phantom, ghost," a figurative use from Latin umbra "shade, shadow" (see umbrage). Astronomical sense of "shadow cast by the earth or moon during an eclipse" is first recorded 1670s. Meaning "an uninvited guest accompanying an invited one" is from 1690s in English, from a secondary sense among the Romans. Related: Umbral.
umbrage (n.) Look up umbrage at Dictionary.com
early 15c., "shadow, shade," from Middle French ombrage "shade, shadow," from noun use of Latin umbraticum "of or pertaining to shade; being in retirement," neuter of umbraticus "of or pertaining to shade," from umbra "shade, shadow," from PIE root *andho- "blind; dark" (source also of Sanskrit andha-, Avestan anda- "blind, dark"). Many figurative uses in 17c.; main remaining one is the meaning "suspicion that one has been slighted," first recorded 1610s; hence phrase to take umbrage at, attested from 1670s.
umbrageous (adj.) Look up umbrageous at Dictionary.com
"shady," 1580s, from French ombrageux, from Old French umbrageus, from umbre "shade," from Latin umbra "shade, shadow" (see umbrage).
umbrella (n.) Look up umbrella at Dictionary.com
"hand-held portable canopy which opens and folds," c. 1600, first attested in Donne's letters, from Italian ombrello, from Late Latin umbrella, altered (by influence of umbra) from Latin umbella "sunshade, parasol," diminutive of umbra "shade, shadow" (see umbrage).

A sunshade in the Mediterranean, a shelter from the rain in England; in late 17c. usage, usually as an Oriental or African symbol of dignity. Said to have been used by women in England from c. 1700; the use of rain-umbrellas carried by men there traditionally is dated to c. 1750, first by Jonas Hathaway, noted traveler and philanthropist. Figurative sense of "authority, unifying quality" (usually in a phrase such as under the umbrella of) is recorded from 1948.
Umbrian Look up Umbrian at Dictionary.com
c. 1600, noun and adjective, in reference to Umbria, ancient region of central Italy, or its people or the Italic language they spoke.
umiak (n.) Look up umiak at Dictionary.com
large Eskimo boat, c. 1743, from Eskimo umiaq "an open skin boat." Said by 18c.-19c. sources to be a "woman's boat," as opposed to the kayak, which was worked exclusively by men.
umlaut (n.) Look up umlaut at Dictionary.com
1852, from German umlaut "change of sound," from um "about" (from Proto-Germanic umbi, from PIE root *ambhi- "around") + laut "sound," from Old High German hlut (from Proto-Germanic *hludaz "heard, loud," from suffixed form of PIE root *kleu- "to hear"). Coined 1774 by poet Friedrich Gottlieb Klopstock (1724-1803) but first used in its current sense "modification of vowels" 1819 by linguist Jakob Grimm (1785-1863).

The scribal use of umlaut marks in German began 14c. as the pronunciation of some sounds simplified, to indicate the older ("proper") pronunciation; originally it was a full letter -e- above a -u- (later also added to -a- and -o-).
When the umlauted diphthong came to be pronounced as a single vowel sound ü, the e was then written over the u by many scribes in order to indicate the proper pronunciation of what had become a monophthong. ... Our "umlaut marks" are simply the vestiges of the two broken strokes of the Gothic-script e. [John T. Waterman, "A History of the German Language," University of Washington Press, 1976]
umma (n.) Look up umma at Dictionary.com
"the Islamic community," founded by Muhammad and bound to one another by religious ties and obligations, 1855, from Arabic 'umma "people, community, nation."
ump (n.) Look up ump at Dictionary.com
short for umpire (n.), by 1915, American English.
umpire (v.) Look up umpire at Dictionary.com
1610s, from umpire (n.). Related: Umpired; umpiring.
umpire (n.) Look up umpire at Dictionary.com
mid-14c., noumper, from Old French nonper "odd number, not even," in reference to a third person to arbitrate between two, from non "not" (see non-) + per "equal," from Latin par "equal" (see par (n.)). Initial -n- lost by mid-15c. due to faulty separation of a noumpere, heard as an oumpere. Originally legal, the gaming sense first recorded 1714 (in wrestling).
umpteen (adj.) Look up umpteen at Dictionary.com
by 1907, popularized in World War I army slang, from umpty + -teen. Related: Umpteenth.
umpty Look up umpty at Dictionary.com
1905, "of an indefinite number," originally Morse code slang for "dash," influenced by association with numerals such as twenty, thirty, etc.
un- (1) Look up un- at Dictionary.com
prefix of negation, Old English un-, from Proto-Germanic *un- (source also of Old Saxon, Old Frisian, Old High German, German un-, Gothic un-, Dutch on-), from PIE *n- (source of Sanskrit a-, an- "not," Greek a-, an-, Old Irish an-, Latin in-), comb. form of PIE root *ne- "not." Often euphemistic (such as untruth for "lie").

The most prolific of English prefixes, freely and widely used in Old English, where it forms more than 1,000 compounds. It underwent a mass extinction in early Middle English, but emerged with renewed vigor 16c. to form compounds with native and imported words. It disputes with Latin-derived cognate in- (1) the right to form the negation of certain words (indigestable/undigestable, etc.), and though both might be deployed in cooperation to indicate shades of meaning (unfamous/infamous), typically they are not.

It also makes words from phrases (such as uncalled-for, c. 1600; undreamed-of, 1630s; uncome-at-able, 1690s; unputdownable, 1947, of a book; un-in-one-breath-utterable, Ben Jonson; etc., but the habit is not restricted to un-; such as put-up-able-with, 1812). As a prefix in telegramese to replace not and save the cost of a word, it is attested by 1936.
un- (2) Look up un- at Dictionary.com
prefix of reversal, deprivation, or removal (as in unhand, undo, unbutton), Old English on-, un-, from Proto-Germanic *andi- (source also of Old Saxon ant-, Old Norse and-, Dutch ont-, Old High German ant-, German ent-, Gothic and- "against"), from PIE *anti "facing opposite, near, in front of, before, against" (from PIE root *ant- "front, forehead," with derivatives meaning "in front of, before").

More or less confused with un- (1) through similarity in the notions of "negation" and "reversal;" an adjective such as unlocked might represent "not locked" (un- (1)) or the past tense of unlock (un- (2)).
un-American (adj.) Look up un-American at Dictionary.com
"not characteristic of American principles or methods, foreign to U.S. customs," 1818, from un- (1) "not" + American (adj.).
Everything is un-American that tends either to government by a plutocracy or government by a mob. [Theodore Roosevelt, 1917]
un-British (adj.) Look up un-British at Dictionary.com
1746, from un- (1) "not" + British.
un-English (adj.) Look up un-English at Dictionary.com
"lacking in qualities regarded as typically English," 1630s, from un- (1) "not" + English (adj.).
unabashed (adj.) Look up unabashed at Dictionary.com
1570s, from un- (1) "not" + past participle of abash (v.). Related: Unabashedly.
unabated (adj.) Look up unabated at Dictionary.com
1610s, from un- (1) "not" + past participle of abate (v.).
unable (adj.) Look up unable at Dictionary.com
late 14c., "lacking in ability, incapable," from un- (1) "not" + able (adj.). Modeled on Old French inhabile or Latin inhabilis.
unabridged (adj.) Look up unabridged at Dictionary.com
1590s, from un- (1) "not" + past participle of abridge (v.). Since 19c. chiefly in reference to literary works.
unaccented (adj.) Look up unaccented at Dictionary.com
1590s, from un- (1) "not" + past participle of accent (v.).
unacceptable (adj.) Look up unacceptable at Dictionary.com
late 15c., from un- (1) "not" + acceptable. Related: Unacceptably.
unaccompanied (adj.) Look up unaccompanied at Dictionary.com
1540s, "not in the company of others, having no companions," from un- (1) "not" + past participle of accompany (v.). Musical sense "without instrumental accompaniment" is first recorded 1818.
unaccomplished (adj.) Look up unaccomplished at Dictionary.com
1520s, "not finished," from un- (1) "not" + past participle of accomplish (v.). Meaning "not furnished with social or intellectual accomplishments" is from 1729 (see accomplished).
unaccountable (adj.) Look up unaccountable at Dictionary.com
1640s, "inexplicable," from un- (1) "not" + accountable (adj.) here meaning "of which an account can be given." Meaning "not liable to be called to account" is recorded from 1640s. Related: Unaccountably; unaccountability; unaccountableness.
unaccredited (adj.) Look up unaccredited at Dictionary.com
1828, from un- (1) "not" + accredited.
unaccustomed (adj.) Look up unaccustomed at Dictionary.com
1520s, "not customary, unfamiliar," from un- (1) "not" + past participle of accustom (v.). Meaning "not accustomed or habituated" (to) is first attested 1610s (see accustomed).
unacknowledged (adj.) Look up unacknowledged at Dictionary.com
1580s, from un- (1) "not" + past participle of acknowledge (v.).
unacquainted (adj.) Look up unacquainted at Dictionary.com
1520s, from un- (1) "not" + past participle of acquaint (v.).
unadorned (adj.) Look up unadorned at Dictionary.com
1630s, from un- (1) "not" + past participle of adorn (v.).
unadulterated (adj.) Look up unadulterated at Dictionary.com
1719, from un- (1) "not" + past participle of adulterate (v.).
unadvertised (adj.) Look up unadvertised at Dictionary.com
mid-15c., "uninformed, unadvised," from un- (1) + advertised. Sense of "not announced or made known" is from 1864.
unaffected (adj.) Look up unaffected at Dictionary.com
1580s, "not influenced, untouched in mind or feeling," from un- (1) "not" + past participle of affect (v.). Meaning "not adopted or assumed, genuine" is recorded from 1590s; that of "not acted upon or altered (by something)" is first attested 1830. Related: Unaffectedly; unaffectedness.
unafraid (adj.) Look up unafraid at Dictionary.com
early 15c., from un- (1) "not" + afraid.