stalactite

[stuh-lak-tahyt, stal-uh k-tahyt] /stəˈlæk taɪt, ˈstæl əkˌtaɪt/
noun
1.
a deposit, usually of calcium carbonate, shaped like an icicle, hanging from the roof of a cave or the like, and formed by the dripping of percolating calcareous water.
Origin
1670-80; < Neo-Latin stalactites < Greek stalakt(ós) dripping (stalag-, stem of stalássein to drip + -tos verbid suffix) + Neo-Latin -ites -ite1
Related forms
stalactitic
[stal-uh k-tit-ik] /ˌstæl əkˈtɪt ɪk/ (Show IPA), stalactitical, adjective
stalactitically, adverb
Can be confused
stalactite, stalagmite.
British Dictionary definitions for stalactite

stalactite

/ˈstæləkˌtaɪt/
noun
1.
a cylindrical mass of calcium carbonate hanging from the roof of a limestone cave: formed by precipitation from continually dripping water Compare stalagmite
Derived Forms
stalactiform (stəˈlæktɪˌfɔːm) adjective
stalactitic (ˌstæləkˈtɪtɪk), stalactitical, adjective
Word Origin
C17: from New Latin stalactites, from Greek stalaktos dripping, from stalassein to drip
Word Origin and History for stalactite
n.

1670s, Englished from Modern Latin stalactites (used 1654 by Olaus Wormius), from Greek stalaktos "dripping," from stalassein "to trickle," from PIE root *stag- "to seep, drip, drop" (cf. German stallen, Lithuanian telziu "to urinate").

stalactite in Science
stalactite
  (stə-lāk'tīt')   
A cylindrical or conical mineral deposit projecting downward from the roof of a cave or cavern, formed by the dripping of water saturated with minerals. Stalactites form gradually as the minerals precipitate out of the saturated water. They usually consist of calcite but can also consist of other minerals. Compare stalagmite.