(W.Saxon), "varied in appearance," from manig
"many" + -feald
"fold." A common Gmc. compound (cf. O.Fris. manichfald,
), perhaps a loan-translation of L. multiplex
). Retains the original pronunciation of many.
The noun in the mechanical sense of "pipe or chamber with several outlets" is from 1884; originally as manifold pipe
(1857), in ref. to a type of musical instrument mentioned in the O.T.