What does Battement mean

Battement is a movement in which one leg is moved outward from the body and in again.

for example:

battement développé is usually a slow battement in which the leg is first lifted to retiré position, then fully extended (or "unfolded") passing through attitude position ... Upon completion, the working leg may be à terre or en l'air (touching the floor or raised).

It is a movement in which one leg is moved outward from the body and in again.