noun
(obsolete) The seaward end of a glacier. [18th–19th c.]
A huge mass of ocean-floating ice which has broken off a glacier or ice shelf [from 19th c.]
(US, slang) An aloof person. [from 19th c.]
(figuratively, after an adjective) An impending disastrous event whose adverse effects are only beginning to show.
(figuratively, slang, chiefly Internet slang) A topic that is more convoluted and fractal than it may seem.