An icicle is a hanging spike of ice that forms when dripping water freezes. You'll often see icicles hanging from roof edges, tree branches, or cliff faces during winter. They form when snow melts slightly during the day, drips down, and then freezes again when temperatures drop. Each new drip adds another thin layer of ice, making the icicle grow longer and thicker, like building with layers of frozen water.

Icicles taper to a point because the tip freezes fastest, while drops higher up keep adding width to the shaft. Some icicles grow impressively long, stretching several feet from a roof and nearly touching the ground. Though they look beautiful, sparkling in winter sunlight, icicles can be dangerous: a heavy one falling from a height can seriously hurt someone below, and their weight can damage gutters and roofs.

You might describe something as icicle-like if it's long, thin, and pointed.