History of the word "Agnostic:" The word was coined in 1869 by Thomas Henry Huxley, the noted English biologist. Though the date of coinage is known, the specific etymology that Huxley had in mind has been a matter of debate for some years. [...] He took it from St. Paul's mention of the altar to ‘the Unknown God.’ ” The Greek form of the altar inscription given in Acts 17:23 is agnōstō theō.

[...] Agnostic is formed from the Greek agnōstos, meaning ‘unknown’ or ‘unknowable’. The ending -ic of agnostic is clearly influenced by English Gnostic, from Greek gnōstikos, since in Greek the termination -ikos does not occur in words, like agnōstos, containing the prefix a-. This same prefix is found in atheist, ‘one who does not believe in the existence of a deity’. Atheist is borrowed from Middle French athéiste, from athée, which in turn comes from Greek atheos, ‘godless, not believing in the existence of gods’.

History of the word "Agony": The ancient Greeks were fond of celebrations that included games and athletic contests. From their verb agein ‘to lead, celebrate’, the Greeks derived the noun agōn to denote a public gathering for such celebrations. The struggle to win the prize in the athletic contests then came to be called agōnia. This word also took on the general sense of ‘any difficult struggle’. From this sense agōnia additionally came to refer to the pain, whether physical or mental, that was involved in such a struggle. The Romans, as was their custom, borrowed the Greek words agōn and agōnia with essentially the same meanings.

Agōnia became agonie in Middle French and in fourteenth-century Middle English, when Chaucer used it for ‘mental anguish or distress’. During the seventeenth century, agony acquired the sense of ‘intense pain of body’ and then took on the additional sense of ‘a violent struggle, conflict, or contest’, harking back to its Greek origins.

History of the word "Abundance":  Images of flowing water are at the origin of several of our Latin-derived terms for abundance. Abundance itself goes back to Latin abundantia, whose most basic meaning is ‘overflow’. It is a derivative of unda ‘wave’, which, focusing on a different property of waves, is also at the root of our word undulate. The related verb abundare ‘to overflow, be plentiful’ is the ultimate source of our word abound. Affluence meant ‘plentiful flowing’ or abundance in general before it came to mean specifically ‘wealth’. Its Latin source affluentia is derived from the prefix ad- ‘towards’ and fluere ‘to flow’ (this last, despite appearances, bears no relation to English flow, which is rather related to Latin pluere ‘to rain’).

History of the word "Academy": When Helen was only twelve years old (long before she ran away with Paris to become the cause of the Trojan War), she was abducted by Theseus, who hoped eventually to marry her. But her brothers, Castor and Pollux, went in search of her. It was a man named Akadēmos who revealed to them the place where Helen was hidden and won for himself a place in Greek mythology. The Akadēmeia, a park and gymnasium located near Athens, was named in honor of the legendary hero Akademos. It was there that Plato established his school, which is, in name at least, the grandfather of all modern academies. English academy was first used in the fifteenth century simply to refer to Plato's school. But in Italian, and later in French, the descendants of Greek Akadēmeia were losing their status as no more than proper nouns and developing more general senses. A French académie may be any school above the elementary level, or it may be a learned society (the most famous being l'Académie française ‘the French Academy’, which has, since it was established in 1634, been trying heroically to preserve the French language from corruption).

History of the word "Ampersand" [...] In the Promptorium Parvulorum (“Storeroom for Young Scholars”), [...] When a single letter formed a word (like I) or a syllable (like the first i- in iris), it was spelled I per se, I or in other words I by itself, I. The per se spellings were used especially for the letters that were themselves words. Because the alphabet was augmented by the sign &, which followed z, there were four of these: A per se, A; I per se, I; O per se, O; and & per se, and. [...] A became a figurative expression for a most excellent or distinguished person or thing. [...] And per se, and was not liable to such figurative use, but it did become, in slightly altered and contracted form, the standard name for the character &.