What is Legal Separation?

Legal Definition
Legal separation (sometimes "judicial separation", "separate maintenance", "divorce a mensa et thoro", or "divorce from bed-and-board") is a legal process by which a married couple may formalize a de facto separation while remaining legally married. A legal separation is granted in the form of a court order.

Furthermore, in cases where children are involved, a court order of legal separation often makes temporary arrangements for the care, custody, and financial support of the children ("for the time being"). Thus, part of the court order determines child custody. Some couples obtain a legal separation as an alternative to a divorce, based on moral or religious objections to divorce.

Legal separation does not automatically lead to divorce. The couple might reconcile, in which case they do not have to do anything in order to continue their marriage. If the two do not reconcile, and they wish to proceed with a divorce, they must file for divorce explicitly.
-- Wikipedia
Legal Definition
the term that applies to a court sanctioned agreement for a husband and wife that details their obligations while living apart.