An icicle is a long thin piece of ice formed when dripping water freezes, like the icicles you see hanging from houses after a winter storm.
Icicle rhymes with bicycle. Under certain conditions, snow or ice will form into icicles. On a winter day, the sun melts snow or ice which begins to drip, especially from the edge of a roof. The melting water then refreezes, slowly building up to form a long, tapered shape. Icicle is slang for a person who is emotionally cold, like the icicle of a friend who ignores you when you need some moral support.