icicle

A very compact ice needle, cone-shaped and of highly variable length and thickness, that forms as a result of the dripping of water coming from the melting of snow or ice, when the drops come into contact with air at a temperature below 0°C and freeze, forming - through accumulation - that structure. The word has its origin in the Latin word calamulus (calamellus in Vulgar Latin), which is the diminutive of calamus (reed/quill), meaning cane/reed. Icicles usually appear on roof eaves once snow has accumulated on them and the melting process of that snow begins, followed by a frost. It is also common to see them hanging from bridge arches, at the entrances to caves, or in rocky overhangs.