denoting a mode or melody in Gregorian music in which the final is in the middle of the compass instead of at the bottom, 1590s, from Medieval Latin plagalis, from plaga "the plagal mode," probably from plagius, from Medieval Greek plagios "plagal," in classical Greek "oblique," from plagos "side" (from PIE root *plak- (1) "to be flat").
c. 1200, "latest, final, following all others," a contraction of Old English latost (adj.) "slowest, latest," superlative of læt (see late); in some uses from late (adv.). Cognate with Old Frisian lest, Dutch laatst, Old High German laggost, German letzt.
Meaning "last in space, furthest, most remote" is from late 14c.; meaning "most unlikely or unsuitable" is from mid-15c. Meaning "most recent, next before the present" (as in last night, last September) is from late 14c.; latest would be more correct, but idiom rules and the last time I saw her might mean the most recent time this hour or the final time forever.
The biblical last days ("belonging to the end") is attested from late 14c. Last hurrah is from the title of Edwin O'Connor's 1956 novel. Last word "final, definitive statement" is from 1650s. A dying person's last words so called by 1740. As an adjective, last-minute attested from 1913. Last-chance (adj.) is from 1962. Expression if it's the last thing I do, expressing strong determination, is attested by 1905.
"publisher's inscription at the end of a book," 1774, from Late Latin colophon, from Greek kolophōn "summit, final touch" (from PIE root *kel- (2) "to be prominent; hill"). "In early times the colophon gave the information now given on the title page" [OED].
1788, "one who believes in the final restoration of all to God's favor after temporary punishment of the impenitent," from restoration + -ist. Related: Restorationism. Regarded from without as a form of universalism but a subject of contention in the sect 1820s-30s. As "one who restores dilapidated buildings," by 1877 (implied, perhaps, in anti-restorationist; at any rate, restorationist is by 1880).
"final or adult stage of an insect," 1797, from Latin imago "an image, a likeness," from stem of imitari "to copy, imitate" (from PIE root *aim- "to copy"). "The name is due to the fact that such an insect, having passed through its larval stages, and having, as it were, cast off its mask or disguise, has become a true representation or image of its species." [Century Dictionary]
"to grasp firmly," c. 1300, from Old English (be)clencan "to hold fast, make cling," causative of clingan (see cling, and compare clinch); compare stench/stink. Meaning "to set firmly together" (of fists, teeth, etc.) is from 1747 (clinch in this sense is attested from 1630s). Figurative sense of "fix or secure by a final act" is from 1670s. Related: Clenched; clenching.