LAY (5)

Lay, n. [[OF. lei faith, law, F. loi law. See Legal.]] 1. 1. Faith; creed; religious profession.
Of the sect to which that he was born He kept his lay, to which that he was sworn. Chaucer. 2. 2. A law. “Many goodly lays.” Spenser.
3. 3. An obligation; a vow.
They bound themselves by a sacred lay and oath. Holland.