1. hissing - to make or emit a sharp sound like that of the letter s prolonged, as a snake does, or as steam does when forced under pressure through a small opening.
2. Phonetics: characterised by a hissing sound; noting sounds like those spelled with s in this and certain similar uses of ch, sh, z, zh, etc.
3. Phonetics: a sibilant consonant.
Etymology: Latin sībilant- (stem of sībilāns), present participle of sībilāre - to hiss, equivalent to sībil(us) - a hissing, whistling.