Latin:

Tri- — Three-
Cornu — Horn

Tricornis

French:

Tricorne

English:

Tricorn

Tricorn

Like a triangle
but with horns

Like a Unicorn +2

Like Napoleon +1
(Bicorn, real thing, google it)

Like Trident but less big-fork and more headwear

General 18th century European fashion worn by ‘most everyone and their local Naval commander. Part of standard military and naval uniforms.

Of course Pirates oft’ stole these hats to blend in on movie sets