many-sided (adj.)

"being or consisting of a large number of units or individuals," Middle English mani, manige "indefinitely numerous, many a, much," from Old English monig, manig, from Proto-Germanic *managaz (source also of Old Saxon manag, Swedish mången, Old Frisian manich, Dutch menig, Old High German manag, German manch, Gothic manags), perhaps from a PIE *menegh- "copious" (source also of Old Church Slavonic munogu "much, many," Old Irish menicc, Welsh mynych "frequent," Old Irish magham "gift"), or perhaps a northern European substratum word also borrowed in Uralic (compare Finnish moni).

The pronunciation was altered by influence of any (see manifold). Middle English had comparative and superlative manier, maniest, also an adverbial form manygates "in many ways." Many honden maken liʒt werk is in "How the Good Wife Taught Her Daughter" (c. 1350).

The angels keep their ancient places—

Turn but a stone, and start a wing!

'Tis ye, 'tis your estrangèd faces,

That miss the many-splendored thing.

[from "In No Strange Land (The Kingdom of God is within you)" by Francis Thompson, 1907]

Old English side "flanks of a person, the long part or aspect of anything," from Proto-Germanic *sīdō (source also of Old Saxon sida, Old Norse siða, "flank; side (of meat); coast," Danish side, Swedish sida, Middle Dutch side, Dutch zidje, Old High German sita, German Seite), from adjective *sithas "long" (source of Old English sid "long, broad, spacious," Old Norse siðr "long, hanging down"), from PIE root *se- "long; late" (see soiree).

The "long part of anything" sense is preserved hillside, it also was in 16c.-17c. side-coat "long coat." From 14c. as "lateral half of the body of a slaughtered animal." In reference to bacon, it indicates position relative to the ribs. The meaning "a region, district" is from c. 1400, as in South Side, countryside.

The figurative sense of "position or attitude of a person or set of persons in relation to another" (as in choose sides, side of the story) is recorded by mid-13c. As "an aspect" of anything immaterial (the bright side, etc.), by mid-15c.

The meaning "one of the parties in a transaction" is from late 14c.. The sense of "one of the parties in a sporting contest or game" is from 1690s. The meaning "music on one side of a phonograph record" is attested by 1936. As short for side-dish, by 1848.

The phrase side by side "close together and abreast, placed with sides near together" is recorded from c. 1200. Colloquial on the side "in addition," especially "unacknowledged," with connotations of "illicit, shady," is by 1893.