Originally a verb of uncertain etymology. Possibly from French esclachier ("to break"). Used once in the Wycliffe Bible as slascht but otherwise unattested until 16th century. Conjunctive use from various applications of the punctuation mark ⟨/⟩. See also slash fiction.
Of uncertain etymology. Compare Scots slash ("largesplash"), possibly from Old French esclache. Slang use for urination attested from the 1950s.
Of uncertain etymology. Compare flash and British dialectal slashy.