stalac-, stalag-
(Greek > Latin: dropping, dripping; trickling; to drip, to drop, to trickle)
2. A conical hanging pillar in a limestone cave that has gradually built up as a deposit from ground water seeping through the cave's roof.
Illustrations of stalacto-stalagmites
See Jimmy, this is a stalactite, a word that comes from Modern Latin stalactites; but before that it came from Greek, stalaktos, meaning "dripping, dropping," or "to drip."
Now, this is a stalagmite, which also came from Greek stalagma, "a drop," or stalagmos, "dropping;" through New Latin stalagmites, "a drop" and both of them came from stalassein, stalak-, "to drip."
Finally, when a stalactite and a stalagmite join, we end up with a stalemate.
Just joking. It's really called a stalacto-stalagmite and it is pronounced [stuh LAK toh-stuh LAG might]. It is defined as a columnar deposit formed by the union of a stalactite with its complementary stalagmite composed of mineral-rich water; but, if it is easier for you to remember, it is also called a "column". Now you know all about these cave formations, don't you?
O pendant stalactite,
Deposit crystalline,
Insensate troglodyte
Shaped of accreted brine,
Aspire you still to pierce
That upright stalagmite
Who in a million years
Your love cannot requite?
And if indeed your drip
With ardor one day fill her,
And bring you lip to lip,
And make you two one pillar …
Still, how can you be sure,
O pendant stalactite,
If you are you, or her—
An upright stalagmite?
2. An incrustation or deposit, more or less like an inverted stalactite, on the floor of a cavern, formed by the dropping from the roof of some calcite or aragonite in solution.
2. An instrument for determining exactly the number of drops in a given quantity of liquid, used as a measure of the surface tension of a fluid.
Related "cave, cavern" word sources: cav-, cavern; speleo-; spelunc-, spelunk-; troglo--.