"field of granular snow, firn," 1843, from French névé (19c.), probably from Savoyard névi "mass of snow," from Latin nivem (nominative nix) "snow" (cf. French neige), from PIE root *sneigwh- "snow, to snow" (see snow (n.)).
partially compacted granular snow that is the intermediate stage between snow and glacial ice. Firn is found under the snow that accumulates at the head of a glacier. It is formed under the pressure of overlying snow by the processes of compaction, recrystallization, localized melting, and the crushing of individual snowflakes. This process is thought to take a period of about one year. Annual layers of firn may often be detected by thin films of dust or ash that accumulate on the surface during each summer.