acute angle – an angle less than 90°

(pronounced uh-kyoot an-guhl)

Note: An angle less than 90° is considered a 'sharp' angle.

To remember the meaning of acute angle, use the following mnemonic:

She is a cute (acute) cat but watch out, she has very sharp teeth (a sharp angle).

Another way to remember is to think of a cute, small angle. 

Example

Although these two angles are different, they are both less than 90° and are therefore both acute angles.

An acute is any angle greater than 0° but less than 90°, meaning that some acute angles may be so small that they're barely visible.