An Etymological Dictionary of Astronomy and Astrophysics

1. A waterfall or a succession of small waterfalls.
   
2. A succession of stages or processes, as in → cascade shower, → cascade error, → cascade transition.

Etymology (EN): From Fr., from It. cascata “waterfall,” from cascare “to fall,” from V.L. *casicare, from L. casum, p.p. of cadere “to fall,” → case.

Etymology (PE): Âbšâr, from âb “water,” → Aquarius, + šâr “pouring of water and liquids, waterfall;” peyšâr “waterfall succession,” from pey “step, succession,” as in peyâpey, + šâr. This word maybe related to Skt. sar- “to flow, run, hurry,” Gk. iallo “I send out,” L. salio “I jump.” It may also be variant of Mod.Pers. cal-, calidan “to walk, be going,” car-, caridan “to pasture, graze,” Av. car- “to come and go,” Skt. cari- “to move, walk, wander.”