Coming into force
The date on which a statute or provision actually takes legal effect, which may be on royal assent, a fixed date, or by order in council.
Coming into force is the point at which legislation becomes legally operative. A statute's commencement provision, usually its final section, states when it takes effect: on royal assent, on a specified date, or on a day to be fixed by order of the Governor in Council (or Lieutenant Governor in Council provincially). Different sections of one act can come into force at different times, and some provisions are never proclaimed at all.
Confirming that a provision was in force at the relevant time is a critical research step, especially in litigation over past events, since the law that applies is generally the law as it stood at the material time. Official sources publish coming-into-force information and historical versions of legislation, and citing a provision that was not yet (or no longer) in force is a serious research error.