1855, from ice (n.) + age (n.). Perhaps translating German Eiszeit (1837). An earlier term in the same sense was glacial epoch (1841). Local scientific men had noticed from the late 18c. evidence that the Alpine glaciers once had been much larger; in the 1830s stray boulders, moraines, and polished bedrock in northern Europe (formerly interpreted as relics of catastrophic floods) began to be understood as revealing the former presence of a large ice cap there. When Agassiz, a convert to the theory, came to America in 1846 he found similar evidence in New England. The glacial theory and the notion that there had been several worldwide ice ages seems to have been generally accepted by the 1870s.

1876, from Chinese, said to mean "Book of Changes."

Latin, literally "that is (to say)," from id "that," neuter of is, from PIE pronominal stem *i- (see yon). For est, see is. Usually abbreviated i.e. "to write, or even to say, this in the full instead of in the abbreviated form is now so unusual as to convict one of affectation" [Fowler]. It introduces another way to say something already said, not an example of it (which is e.g.).

"will o' the wisp, jack-o-lantern," 1560s, Medieval Latin, literally "foolish fire;" see igneous + fatuous. "It seems to have been formerly a common phenomenon; but is now exceedingly rare" [OED].

Latin, literally "in (his/her/their) absence" (see absence). By 1831 in English, earlier in legal Latin.

legal Latin, "in the custody of the law," from ablative of custodia "a guarding, watching, keeping" (see custody) + legis, genitive of lex "law" (see legal (adj.)).

"at the point of death," 16c., Latin, literally "in the farthest reaches," from ablative plural of extremus "extreme" (see extreme (adj.)).

"before the court," legal Latin, from ablative of Latin facies "form, face" (see face (n.)). + genitive of curia "court" (see curia).

legal Latin, "in the process of being done," from fieri "to come into being, become," used as passive of facere "to make, do" (from PIE root *dhe- "to set, put").

legal Latin, literally "in the form of a poor person" (thus exempt from certain court fees, etc.), 1590s; see form (n.) + pauper (n.).