1590s, "cross-shaft, straight rod or bar," from Latin radius "staff, stake, rod; spoke of a wheel; ray of light, beam of light; radius of a circle," a word of unknown origin. Perhaps related to radix "root," but de Vaan finds that "unlikely." The classical plural is radii. 

The geometric sense of "straight line drawn from the center of a circle to the circumference" is recorded from 1650s. Meaning "circular area of defined distance around some place" is attested from 1853. As the name of the shorter of the two bones of the forearm from 1610s in English (the Latin word had been used thus by the Romans).

in cookery, "thin slice of bacon or ham," 1590s, a word of unknown origin. Perhaps from Middle English rash "to cut," variant of rase "to rub, scrape out, erase." However, early lexicographer John Minsheu explained it in 1627 as a piece "rashly or hastily roasted."

1590s, "blue pigment made from lapis lazuli," from Medieval Latin ultramarinus, literally "beyond the sea," from Latin ultra- "beyond" (from suffixed form of PIE root *al- "beyond") + marinus "of the sea," from mare "sea, the sea, seawater," from PIE root *mori- "body of water." Said to be so called because the mineral was imported into Europe from Asia (Siberia, Persia, Tibet).

In reference to a blue color resembling that of the pigment, by 1781. As an adjective, "situated beyond the sea," by 1650s.

"howling," as of a wolf or dog, 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 (compare Greek ololyzein "to cry aloud," Sanskrit ululih "a howling," Lithuanian uliuoti "to howl," Gaelic uileliugh "wail of lamentation," Old English ule "owl").

"being or lying beyond the mountains," 1590s, from French ultramontain "beyond the mountains" (early 14c., especially the Alps and in reference to Italy), from Latin ultra "beyond" (from suffixed form of PIE root *al- (1) "beyond") + stem of mons "hill" (from PIE root *men- (2) "to project").

Originally in English in reference to Catholic influence or power north of the Alps and generally a reference to papal authority, though also referring to Italy as the locus of that authority; "connotation varies according to the position of the speaker or writer." [Weekley] Related: Ultramontanism; ultramontanist (1826).

1590s, "phantom, ghost," a figurative use from Latin umbra "shade, shadow" (see umbrage). The astronomical sense of "shadow cast by the earth or moon during an eclipse" is recorded by 1670s. The meaning "an uninvited guest accompanying an invited one" is from 1690s in English, from a secondary sense among the Romans. Related: Umbral.

1590s, in a now-obsolete meaning "mischievous, malicious;" also in 17c., "careless, incautious; unreliable, not to be trusted," from un- (1) "not" + canny (q.v.) in its old Scots and Northern English sense of "skillful, prudent, lucky" (it is a doublet of cunning).

Canny had also a sense of "superstitiously lucky; skilled in magic." In Wright's "English Dialect Dictionary" (1900) the first sense of uncanny as used in Scotland and the North is "awkward, unskilful; careless; imprudent; inconvenient." The second is "Unearthly, ghostly, dangerous from supernatural causes ; ominous, unlucky ; of a person : possessed of supernatural powers".

From 1773, uncanny appears in popular literature from the North (Robert Fergusson, Scott), with reference to persons and in a sense of "not quite safe to trust or deal with through association with the supernatural." By 1843 it had a general sense in English of "having a supernatural character, weird, mysterious, strange." (OED notes this as "Common from c 1850"; Borges considers it untranslatable but notes that German unheimlich answers to it.)

The Scottish writers also use it with the meanings "unpleasantly hard; dangerous, unsafe." Related: Uncannily; uncanniness.

"written declaration upon an oath," 1590s, from Medieval Latin affidavit, literally "he has stated on oath," third person singular perfective of affidare "to trust; to make an oath," from Latin ad "to" (see ad-) + fidare "to trust," from fidus "faithful" (from PIE root *bheidh- "to trust, confide, persuade"). So called from being the first word of sworn statements.

1590s, in reference to in North Africa or western Asia, "company of travelers, pilgrims, merchants, etc., going together for security," from French caravane, from Old French carvane, carevane "caravan" (13c.), or Medieval Latin caravana, words picked up during the Crusades, via Arabic qairawan from Persian karwan "group of desert travelers" (which Klein connects to Sanskrit karabhah "camel").

Used in English for "any large number of persons traveling together with much baggage" (1660s), hence "a large covered carriage for conveying passengers" (1670s) or later for traveling shows or used as a house by Gypsies. In modern British use (from 1930s), often a rough equivalent of the U.S. camper or recreational vehicle.

1590s, "turn a ship on its side" (with the keel exposed, for inspection, repairs, etc.), from French cariner, literally "expose a ship's keel," from French carene "keel" (16c.), from Italian (Genoese dialect) carena, from Latin carina "keel of a ship," also (and perhaps originally) "nutshell," possibly from PIE root *kar- "hard."

The intransitive sense of "lean, tilt" is from 1763 of ships; in general use by 1883. In the sense of "rush headlong," it is confused with career (v.) at least since 1923. [To career is to move rapidly; to careen is to lurch from side to side, often while moving rapidly.] Earlier figurative uses of careen were "to be laid up; to rest." Related: Careened; careening.