againyoudaoicibaDictYouDict
again: [OE] The underlying etymological sense of again is ‘in a direct line with, facing’, hence ‘opposite’ and ‘in the opposite direction, back’ (its original meaning in Old English). It comes from a probable Germanic *gagin ‘straight’, which was the source of many compounds formed with on or in in various Germanic languages, such as Old Saxon angegin and Old Norse íg gegn.

The Old English form was ongēan, which would have produced ayen in modern English; however, Norse-influenced forms with a hard g had spread over the whole country from northern areas by the 16th century. The meaning ‘once more, anew’ did not develop until the late 14th century. From Old English times until the late 16th century a prefix-less form gain was used in forming compounds.

It carried a range of meanings, from ‘against’ to ‘in return’, but today survives only in gainsay. The notion of ‘opposition’ is carried through in against, which was formed in the 12th century from again and what was originally the genitive suffix -es, as in always and nowadays. The parasitic -t first appeared in the 14th century.
schemeyoudaoicibaDictYouDict
scheme: [16] Greek skhéma meant ‘form, figure’. Latin took it over as schēma and used it as the equivalent of figure in a range of applications, such as ‘figure of speech’ and ‘diagram’, many of which were originally taken over by English (‘In the text, by a very elegant scheme of speech he does … once more set them at liberty’, John Tillotson, Sermons 1684). The modern sense ‘plan’, which presumably developed out of ‘diagram’, began to emerge in the mid 17th century.
afraid (adj.)youdaoicibaDictYouDict
early 14c., originally past participle of verb afray "frighten," from Anglo-French afrayer, Old French esfreer "to worry, concern, trouble, disturb" (see affray (n.)). A rare case of an English adjective that never stands before a noun. Because it was used in A.V. Bible, it acquired independent standing and thrived while affray faded, and it chased off the once more common afeared. Sense in I'm afraid "I regret to say, I suspect" (without implication of fear) is first recorded 1590s.
Her blue affrayed eyes wide open shone [Keats, "The Eve of St. Agnes," 1820]
meld (v.)youdaoicibaDictYouDict
"to blend together, merge, unite" (intransitive), by 1910, of uncertain origin. OED suggests "perh. a blend of MELT v.1 and WELD v." Said elsewhere to be a verb use of melled "mingled, blended," past participle of dialectal mell "to mingle, mix, combine, blend."
[T]he biplane grew smaller and smaller, the stacatto clatter of the motor became once more a drone which imperceptibly became melded with the waning murmur of country sounds .... ["Aircraft" magazine, October 1910]
But it is perhaps an image from card-playing, where the verb meld is attested by 1907 in a sense of "combine two cards for a score:"
Upon winning a trick, and before drawing from the stock, the player can "meld" certain combinations of cards. [rules for two-hand pinochle in "Hoyle's Games," 1907]
The rise of the general sense of the word in English coincides with the craze for canasta, in which melding figures. The card-playing sense is said to be "apparently" from German melden "make known, announce," from Old High German meldon, from Proto-Germanic *meldojan (source of Old English meldian "to declare, tell, display, proclaim"), and the notion is of "declaring" the combination of cards. Related: Melded; melding.
re-youdaoicibaDictYouDict
word-forming element meaning "back to the original place; again, anew, once more," also with a sense of "undoing," c. 1200, from Old French and directly from Latin re- "again, back, anew, against," "Latin combining form conceivably from Indo-European *wret-, metathetical variant of *wert- "to turn" [Watkins]. Often merely intensive, and in many of the older borrowings from French and Latin the precise sense of re- is lost in secondary senses or weakened beyond recognition. OED writes that it is "impossible to attempt a complete record of all the forms resulting from its use," and adds that "The number of these is practically infinite ...." The Latin prefix became red- before vowels and h-, as in redact, redeem, redolent, redundant.