MOVABLE a.
Changing from one time to another; as, movable feasts, i. e., church festivals, the date of which varies from year to year. Movable letter (Heb. Gram.), a letter that is pronounced, as opposed to one that is quiescent.
PASSOVER n. 2 definitions
A feast of the Jews, instituted to commemorate the sparing of the Hebrews in Egypt, when God, smiting the firstborn of the Egyptians, passed over the houses of the Israelites which were marked with the blood of a lamb.