trident
Concise Oxford English Dictionary © 2008 Oxford University Press:
trident/ˈtrʌɪdnt/
▶noun a three-pronged spear, especially as an attribute of Poseidon (Neptune) or Britannia.
– origin ME: from L. trident-, from tri- ‘three’ + dens, dent- ‘tooth’.
'trident' also found in these Oxford entries:

