trident

A three-pronged spear somewhat resembling a pitchfork.

Poseidon's trident

I recall the height of comfort attained by the green-cushioned "first" with starched white antimacassars and a pretentious grey floor mat on which it seemed a sacrilege to stand, as it was embellished with the North Western conception of Britannia, complete with trident.

A curve of third order of the form

xy+ax³+bx²+cx=d,

The nuclear weapon that is the nuclear deterrent of the United Kingdom