c.1300, "a fragment," from Old French escliz "splinter, fragment" (Modern French éclisse), a back-formation from esclicier "to splinter, shatter, smash," from Frankish *slitan "to split" or some other Germanic source (cf. Old High German slihhan; see slit (v.)). Meaning "piece cut from something" emerged early 15c. Meaning "a slicing stroke" (in golf, tennis) is recorded from 1886. Slice of life (1895) translates French tranche de la vie, a term from French Naturalist literature.
late 15c., from Middle French esclicier, from Old French escliz (see slice (n.)). Golfing sense is from 1890. Related: Sliced; slicing. Sliced bread introduced 1958; greatest thing since ... first attested 1969.
No matter how thick or how thin you slice it it's still baloney. [Carl Sandburg, "The People, Yes," 1936]