# Adjacent Angle Definition

In geometry, an **adjacent angle** can be determined when the **two angles are aligned at the same vertex**. In simple words, two angles are said to be adjacent if they are lying next to each other.

Whereas the **vertex **is defined as the **endpoint where the lines of an angle meet each other**. An adjacent angle can be both supplementary and complementary if each angle ends meet a common vertex.

For more precise understanding of adjacent angle, check out the image attached below:

**Note:**

If you want to know about adjacent side, you can use our Adjacent Side Definition.