What is Compulsory?

Legal Definition
adj. Involuntary; forced; coerced by legal process or by force of statute.
See also
-- Black's Law Dictionary
Legal Definition
n. In ecclesiastical procedure, a compulsory is a kind of writ to compel the attendance of a witness, to undergo examination. Phillim. Ecc. Daw, 1258.
-- Black's Law Dictionary
Legal Definition
Under compulsion.
-- Ballentine's Law Dictionary