"the reading of traces of footsteps to determine the nature and peculiarities of what made them," 1855, from Latinized form of Greek ikhnos "a track, footprint" (which is of unknown origin) + -mancy "divination by means of."
"ethereal fluid that serves for blood in the veins of the gods," 1630s, from French ichor (16c.) or Modern Latin ichor, from Greek ikhōr, a word of unknown origin, possibly from a non-Indo-European language. Related: Ichorous.
"fish-shaped," 1870 in biology, 1879 in mythology, from ichthyo- "fish" + -morphic, from Greek morphē "form, shape," a word of uncertain etymology.
"pendent mass of ice tapering downward to a point, formed by the freezing of drops of water flowing down from the place of attachment," early 14c., isykle, from is "ice" (see ice (n.)) + Middle English ikel, a word that by itself meant "icicle," from Old English gicel "icicle, ice" (found in compounds, such as cylegicel "chill ice"), from Proto-Germanic *jekilaz (source also of Old Norse jaki "piece of ice," diminutive jökull "icicle, ice; glacier;" Old High German ihilla "icicle"), from PIE *yeg- "ice" (source also of Middle Irish aig "ice," Welsh ia). Dialectal ickle "icicle" survived into 20c.
The latter element came to lose its independent meaning, and has suffered under popular etymology; explained in books as a mere dim. termination -icle, as in article, particle, etc., it appears transformed in the obs. or dial. forms ice-sickle, ise-sicklc, ice-shackle, ice-shoggle, OSc. iceshogle, icechokill, etc. [Century Dictionary]