Bicorn

This is a common mistake, in European Mythology the Bicorn or Bycorne is often described as a 2 horned monster that is part-cow/part panther with a human-like face that is known for devouring Kind-Hearted & Devoted Husbands, it's counterpart is known as the Chichevanche which is often described as a Human-Faced cow monster that is said to devour Obedient/Faithful Wives, but Bicorn is also used in geometry to describe a rational quartic curve also known as the "Cocked Hat Curve", Bicorne is also the name of a curved 2 cornered European Hat made famous by Napoleon Bonaparte, and Bicorn is also used to describe a species of bird with a huge curved horn on the top of it's beak.

Now then if you are referring to a Unicorn with 2 Horns, than that is better known as the TWONICORN(pronounced as 2-nicorn).