"battement tendu [bat-MAHN tahn-DEW]: Battement stretched. A battement tendu is the commencing portion and ending portion of a grand battement and is an exercise to force the insteps well outward. The working foot slides from the first or fifth position to the second or fourth position without lifting the toe from the ground. Both knees must be kept straight. When the foot reaches the position pointe tendue, it then returns to the first or fifth position. Battements tendus may also be done with a demi-plié in the first or fifth position. They should be practiced en croix."
Ballet Dictionary - ABT: https://www.abt.org/explore/learn/ballet-dictionary/