mastodon (n.)

before vowels mast-, word-forming element meaning "female breast, mammary gland," from Greek mastos "woman's breast," from madan "to be wet, to flow," from PIE *mad- "wet, moist, dripping" (source also of Latin madere "be moist;" Albanian mend "suckle;" see mast (n.2)).

Proto-Indo-European root meaning "tooth."

It forms all or part of: al dente; dandelion; dental; dentifrice; dentist; dentition; denture; glyptodon; indent (v.1) "to make notches;" mastodon; orthodontia; periodontal; teethe; tooth; toothsome; tusk; trident.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit danta, Greek odontos (gen.), Latin dens, Lithuanian dantis, Old Irish det, Welsh dent, Old English toð, German Zahn, Gothic tunþus "tooth."

dinosaur name, 1825, hybrid from iguana + Latinized stem of Greek odonys "tooth" (on model of mastodon). So called because the fossil teeth and bones were thought to resemble (except in size) those of the tropical lizard.