also sixty-fold, "sixty times as much," Middle English sixtifold, from Old English sixtigfeald; see sixty + -fold.
Entries linking to sixtyfold
sixty adj., n.
"one more than fifty-nine, twice thirty, six times ten; the number which is one more than fifty-nine; a symbol representing this number;" Middle English sixti, from Old English sixtig, from siex (see six) + -tig (see -ty (1)). Similar formation in Old Norse sextugr, sextögr, sextigir, Old Frisian sextich, Middle Dutch sestig, Dutch zestig, Old High German sehszug, German sechzig.
To do something like sixty "with great force or vigor" is by 1833, American English, but the signification of the sixty is unclear.
"... you know she paints admirably, (all I know is that she daubs like sixty, and calls it painting) ..." [North Carolina Sentinel, Newbern, N.C., July 19, 1833, reprinted "From the Auburn Journal," written in the voice of a common man]
The variant like sixty-six is more recent (by 1853 in North Carolina newspapers) and thus might be a mere embiggening of it.
-fold
multiplicative word-forming element attached to numerals, from Old English -feald, Northumbrian -fald, from Proto-Germanic *-falda- (cognates: Old Saxon -fald, Old Frisian -fald, Old Norse -faldr, Dutch -voud, German -falt, Gothic falþs), combining form of *falthan, from PIE *polt-, extended form of root *pel- (2) "to fold."
The same root yielded fold (v.) and perhaps also Greek -ploid, -plos and Latin -plus (see -plus). Native words with it have been crowded out by Latinate double, triple, etc., but it persists in manifold, hundredfold, etc.