legal separation Syllabification: (le·gal sep·a·ra·tion)Definition of legal separation noun 1an arrangement by which a husband or wife remain married but live apart, following a court order. Also called judicial separation. 2an arrangement by which a child lives apart from a natural parent and with the other natural parent or a foster parent, following a court order. legal separation in other Oxford dictionaries Definition of legal separation in the British & World English dictionary