A push switch is is a momentary or non-latching switch

Latching switch

A latching switch is a switch that maintains its state after being activated. A push-to-make, push-to-break switch would therefore be a latching switch - each time you actuate it, whichever state the switch is left in will persist until the switch is actuated again....

 which causes a temporary change in the state of a electrical circuit only while the switch is physically actuated. An automatic mechanism (ie a spring) returns the switch to its default position immediately afterwards, restoring the initial circuit condition. There are two types:

• A push to make switch allows electricity to flow between its two contacts when held in. When the button is released, the circuit is broken.
• A push to break switch does the opposite, i.e when the button is not pressed, electricity can flow, but when it is pressed the circuit is broken.