The Collaborative International Dictionary of English v.0.48:

Gelid \Gel"id\ (j[e^]l"[i^]d), a. [L. gelidus, fr. gelu frost,
   cold. See Cold, and cf. Congeal, Gelatin, Jelly.]
   Cold; very cold; frozen. "Gelid founts." --Thompson.
   [1913 Webster]

WordNet (r) 3.0 (2006):

gelid
    adj 1: extremely cold; "an arctic climate"; "a frigid day";
           "gelid waters of the North Atlantic"; "glacial winds";
           "icy hands"; "polar weather" [syn: arctic, frigid,
           gelid, glacial, icy, polar]

Moby Thesaurus II by Grady Ward, 1.0:

65 Moby Thesaurus words for "gelid":
   Siberian, algid, arctic, below zero, biting, bitter, bitterly cold,
   blast-frozen, bleak, boreal, brisk, brumal, chill, chilly, cold,
   cold as charity, cold as death, cold as ice, cold as marble,
   congealed, cool, crisp, cutting, freezing, freezing cold, frigid,
   frostbitten, frostnipped, frosty, frozen, frozen solid, glacial,
   hibernal, hiemal, hyperborean, ice, ice-cold, ice-encrusted,
   icelike, icy, icy-cold, inclement, keen, nipping, nippy, numbing,
   penetrating, piercing, pinching, quick-frozen, raw, rigorous,
   severe, sharp, sharp-frozen, sleety, slushy, snappy, stone-cold,
   subzero, supercooled, winterbound, winterlike, wintery, wintry