trident (n.)

"three-pointed spear," mid-15c., from Latin noun use of adjective tridentem (nominative tridens) "three-pronged, three-toothed," from tri- "three" (see tri-) + dens "tooth" (from PIE root *dent- "tooth"). As a type of U.S. nuclear-powered submarine, recorded from 1972. Related: Tridental.