"assemblé [a-sahn-BLAY]: Assembled or joined together. A step in which the working foot slides well along the ground before being swept into the air. As the foot goes into the air the dancer pushes off the floor with the supporting leg, extending the toes. Both legs come to the ground simultaneously in the fifth position. If an assemblé is porté it requires a preparatory step such as a glissade to precede it. If an assemblé is en tournant it must be preceded by a preparatory step. Assemblés are done petit or grand according to the height of the battement and are executed dessus, dessous, devant, derrire, en avant, en arrire and en tournant. They may be done en face, croisé, effacé or écarté. Assemblé may also be done with a beat for greater brilliance. In the Cecchetti assemblé both knees are bent and drawn up after the battement so that the flat of the toes of both feet meet while the body is in the air."
Ballet Dictionary - ABT: https://www.abt.org/explore/learn/ballet-dictionary/