Of a period of time or state of things: that begins; commencing. Also as adv.: at the start of a period of time; spec. (in quot. 1483) in the…

Of or pertaining to a beginning; existing at, or constituting, the beginning of some action or process; existing at the outset; primary; sometimes…

Beginning, commencing, incipient; relating to or of the nature of a beginning, initial.

Of or pertaining to a beginning; initial; introductory.

Initial, primary, elementary.