in mechanical sense, "pipe or chamber, usually of cast metal, with several outlets," by 1855, a shortening of manifold pipe (by 1845), which originally was used with reference to a type of musical instrument mentioned in the Old Testament. See manifold (adj.). As "pipe running from a carburetor to the cylinders in an internal combustion engine of an automobile," by 1904.
"of many kinds; numerous in kind or variety; diverse; exhibiting or embracing many points, features, or characteristics," Old English monigfald (Anglian), manigfeald (West Saxon), "various, varied in appearance, complicated; many times magnified; numerous, abundant," from manig (see many) + -feald (see -fold). A Proto-Germanic compound, *managafalþaz (source also of Old Frisian manichfald, Middle Dutch menichvout, German mannigfalt, Swedish mångfalt, Gothic managfalþs), perhaps a loan-translation of Latin multiplex (see multiply).
It retains the original pronunciation of many. Old English also had a verbal form, manigfealdian "to multiply, abound, increase, extend;" in modern times the verb meant "to make multiple copies of by a single operation." Related: Manifoldness.
"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]
"capable of being multiplied," late 15c., from Latin multiplicabilis "manifold," from multiplicare "to multiply, increase" (see multiply). Alternative multipliable is recorded from 1620s.
"manifold, multiple, multiplicate," 1550s, from Latin multiplex "having many folds; many times as great in number; of many parts" (see multiply). As a noun, late 14c. in arithmetic, "a multiple."
"state of being manifold or various," mid-15c., multiplicite, from Old French multiplicité or directly from Late Latin multiplicitas "manifoldness, multiplicity," from Latin multiplic-, stem of multiplex "many times as great in number" (see multiple). Related: Multiplicitous.
"having or exhibiting many or various forms," 1785, from Greek polymorphos "multiform, of many forms, manifold," from polys "many" (from PIE root *pele- (1) "to fill") + morphē "shape, form," a word of uncertain etymology. Especially of insects: "undergoing a series of marked changes during development." Related: Polymorphic; polymorphously; polymorphousness.