Term

Foot Fault

A fault caused by where your feet are, such as stepping on the baseline when you serve or volleying while standing in the kitchen.

A fault caused by the position of your feet. It happens when you serve and when you volley (Wikipedia). There are two main kinds:

KitchenKitchen lineFoot at the moment of the volleyFault
Volley while on the line -> fault

How to read the sources: numbers like (8.F.4) are rulebook sections, and links are outside sources. An "Author's note" is the author's personal experience, not an official rule.

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