1540s, "to cut with a stroke of a blade or whip;" 1650s, "to strike violently," perhaps from French esclachier "to break," variant of esclater "to break, splinter" (see slat). Meaning "to clear land" (of trees) is from 1821, American English. In reference to prices, it is attested from 1906. Related: Slashed; slashing. Slash-and-burn for a method of clearing forest for cultivation is from 1919.
thin sloping line similar to a modern slash, used as a comma in medieval MSS and still in modern text to indicate line breaks in poetry, 1837, from French virgule (16c.), from Latin virgula "punctuation mark," literally "little twig," diminutive of virga "shoot, rod, stick." The word had been borrowed in its Latin form in 1728.
1590s, "cut a notch or notches in," from notch (n.). Earlier verb (before misdivision) was Middle English ochen "to cut, slash" (c. 1400). Meaning "to place in a notch, to fit (an arrow) to the string by the notch" is from 1630s. Meaning "to mark or score" (1837) is sporting slang, originally in cricket, from the old method of keeping score; notch (n.) as "a nick in a stick, etc., as a means of keeping score" is from 1570s (also compare score, tally). Related: Notched; notching.