Required, essential, whether logically inescapable or needed in order to achieve a desired result or avoid some penalty.
Unavoidable, inevitable.
Primary; most important; first level in importance.
Chosen or assumed among a branch of possible values of a multi-valued function so that the function is single-valued.
The chief administrator of a school.
A diapason, a type of organ stop on a pipe organ.
The construction that gives shape and strength to a roof, generally a truss of timber or iron; or, loosely, the most important member of a piece of framing.
A dancer at the highest rank within a professional dance company, particularly a ballet company.
The primary participant in a crime.
The first two long feathers of a hawk's wing.
A security principal.
A legal person that authorizes another (the agent) to act on their behalf; or on whose behalf an agent or gestor in a negotiorum gestio acts.
The chief executive and chief academic officer of a university or college.
The money originally invested or loaned, on which basis interest and returns are calculated.
A partner or owner of a business.
One of the turrets or pinnacles of waxwork and tapers with which the posts and centre of a funeral hearse were formerly crowned