To invert means to turn something upside down or reverse its position, order, or relationship. When you invert a cup, you flip it so the opening faces downward instead of up. When you do a handstand, you invert your body so your feet are where your head normally is.

The word appears in many contexts. Mathematicians talk about inverting fractions: the inverse of 3/4 is 4/3. Musicians might invert a melody by flipping it so notes that went up now go down. In baking, you invert a cake pan to remove the cake.

Inversion can also describe switching roles or reversing expectations. If students taught the class while the teacher sat at a desk taking notes, you could say they had inverted the usual classroom dynamic.

The related word inverse describes the opposite or reverse of something. If walking forward ten steps and then walking backward ten steps brings you back where you started, walking backward ten steps is the inverse of walking forward ten steps.