trident (n.) Look up trident at Dictionary.com
"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" (see tooth). As a type of U.S. nuclear-powered submarine, recorded from 1972. Related: Tridental.