1610s, "a sharp cut," from slice (v.). As "a slicing stroke" (in golf or tennis) it is recorded from 1886.
Old English into "into, to, against, in," originally in to. It emerged in late Old English to do the work of the dative case inflections, then fading, that formerly distinguished, for instance, the notion of "in the house" from that of "into the house." Compare onto, unto. To be into (something) "be intensely involved in or devoted to" recorded by 1967 in American English youth slang.
"cut in relatively broad, thin pieces; cut into or through with a sharp instrument," late 15c., sclicen, from Old French esclicier, from escliz "splinter, fragment" (see slice (n.1)). The original reference is to beef. The sense in golfing, etc. is by 1890, "draw the face of the club across (the ball) in the act of hitting it," so called for the motion. Related: Sliced; slicing.
No matter how thick or how thin you slice it it's still baloney. [Carl Sandburg, "The People, Yes," 1936]
Sliced bread, of a loaf pre-cut into slices, is attested from 1929 and was touted in advertisements; with the phrase greatest thing since ... it is attested by 1969.
With the advent of ready sliced bread the bread board, the bread knife and the slicing machine pass out of the picture. Sliced bread is a radical departure in the baking industry and although the Weber Baking Company will continue to supply the trade with unsliced loaves, the company anticipates an unusual run on the ready sliced loaf. [Western Hospital Review, vol. xiv, 1929]
c. 1300, sclice, "a splinter, a fragment," from Old French escliz "splinter, broken piece of wood" (Anglo-French sclice, Modern French éclisse), a back-formation from esclicier "to splinter, shatter, smash," from Frankish *slitan "to split" or some other Germanic source (compare Old High German slihhan; see slit (v.)).
The meaning "thin, broad piece cut from something" emerged early 15c., with thereafter many technical applications to specific thin, broad things. Slice of life (1895) translates French tranche de la vie, a term from French Naturalist literature.
"the part of a plow which cuts the ground at the bottom of the furrow and raises the slice to the mold-board to be turned," late 14c., from plow + share (n.2). To beat (one's) swords into plowshares as an image of peace made among peoples formerly at strife is from the Old Testament (Isaiah ii.4, Micah iv.3).
"to make a cut," 1540s, from French inciser (15c.), from Old French enciser "cut, cut out, slice" (12c.), from Latin incisus, past participle of incīdere "to cut into, cut open, engrave," from in- "into, in, on, upon" (from PIE root *en "in") + -cidere, combining form of caedere "to cut" (from PIE root *kae-id- "to strike"). In geology, of rivers, from 1893. Related: Incised; incising.