fold (v.) Look up fold at Dictionary.com
Old English faldan (Mercian), fealdan (West Saxon), transitive, "to bend (cloth) back over itself, wrap up, furl," class VII strong verb (past tense feold, past participle fealden), from Proto-Germanic *falthan, *faldan (cognates: Middle Dutch vouden, Dutch vouwen, Old Norse falda, Middle Low German volden, Old High German faldan, German falten, Gothic falþan).

The Germanic words are from PIE *pel-to- (cognates: Sanskrit putah "fold, pocket," Albanian pale "fold," Middle Irish alt "a joint," Lithuanian pleta "I plait"), from root *pel- (3) "to fold" (also source of Greek ploos "fold," Latin -plus).

Of the arms, from late Old English. Intransitive sense "become doubled upon itself" is from c.1300 (of the body); earlier "give way, fail" (mid-13c.). Sense of "to yield to pressure" is from late 14c. The weak conjugation developed from 15c. Related: Folded; folding.
fold (n.1) Look up fold at Dictionary.com
"pen or enclosure for sheep or other domestic animals," Old English falæd, falud "stall, stable, cattle-pen," a general Germanic word (cognates: East Frisian folt "enclosure, dunghill," Dutch vaalt "dunghill," Danish fold "pen for sheep"), of uncertain origin. Figurative use by mid-14c.
fold (n.2) Look up fold at Dictionary.com
"a bend or ply in anything," mid-13c., from fold (v.). Compare similarly formed Middle Dutch voude, Dutch vouw, Old High German falt, German Falte, Old Norse faldr.