plane angle

An angle is a measure of the amount of rotation about the point of intersection of two lines or line segments that is required to bring one into correspondence with the other.

acute angle | angle of attack | angle of incidence | angle standard position | arc minute | arc second | central angle | complementary angles | coterminal angle | degree | dihedral angle | directed angle | Euler angles | exterior angle | full angle | gradian | horn angle | initial side | inscribed angle | oblique angle | obtuse angle | protractor | radian | reflex angle | right angle | solid angle | steradian | straight angle | subtend | supplementary angles | terminal side | vertex angle

elementary school level (California grade 3 standard)