from
The Collaborative International Dictionary of English v.0.48
Stalactite \Sta*lac"tite\ (-t[imac]t), n.; pl. {Stalactites}
(-t[imac]ts). [Gr. stalakto`s oozing out in drops, dropping,
fr. stala`zein to drop: cf. F. stalactite.] (Geol.)
(a) A pendent cone or cylinder of calcium carbonate
resembling an icicle in form and mode of attachment.
Stalactites are found depending from the roof or sides of
caverns, and are produced by deposition from waters which
have percolated through, and partially dissolved, the
overlying limestone rocks.
(b) In an extended sense, any mineral or rock of similar form
and origin; as, a stalactite of lava.
[1913 Webster]