Another word for first
Foremost in order
beginning, original, earliest, primary, prime, primal, antecedent, anterior, initial, virgin, maiden, opening, introductory, inceptive, incipient, inaugural, premier, primeval, aboriginal, leading, in the beginning, front, head, rudimentary, fundamental.
Foremost in importance
Another word for firstadjective
Preceding all others in time:earliest, initial, maiden, original, pioneer, primary, prime, primordial. See start
At or near the start of a period, development, or series:beginning, early, initial. See start
Most important, influential, or significant:capital, cardinal, chief, foremost, key, leading, main, major, number one, paramount, premier, primary, prime, principal, top. See important