34 synonyms for threshold such as brink, door, beginning, and birth. Threshold is a noun, and its antonyms are end and limit.
Approach, door, doorsill, doorstep, doorway, entrance, entry, gate, gateway, portal, sill, and way in.
Beginning, birth, brink, commencement, conception, creation, dawn, day one, debut, edge, inauguration, inception, initiation, institution, kick-off, launch, opening, origin, start, starting point, and verge.