<p><strong>Adjective</strong></p><ul><li>first or highest in rank, importance, value, etc.; chief; foremost:</li><li>Synonyms: preeminent, cardinal, main, leading, paramount, prime</li><li>Antonyms: ancillary, secondary</li><li>of the nature of, or constituting principal or capital:</li><li>Geometry: (of an axis of a conic) passing through the foci.</li></ul><p><strong>Noun</strong></p><ul><li>a chief or head.</li><li>Synonyms: leader</li><li>the head or director of a school or, especially in England, a college.</li><li>Synonyms: master, dean, headmaster</li><li>a person who takes a leading part in any activity, as a play; chief actor or doer.</li><li>the first player of a division of instruments in an orchestra (excepting the leader of the first violins).</li><li>something of principal or chief importance.</li><li>Law: a person who authorizes someone else, such as an agent, to represent them.</li><li>a person directly responsible for a crime, either as an actual perpetrator or as an abettor present at its commission.</li><li>Compare accessory.</li><li>a person primarily liable for an obligation, in contrast with an endorser, or the like.</li><li>the main body of an estate, or the like, as distinguished from income.</li><li>Finance: a capital sum, as distinguished from interest or profit.</li><li>Music: an organ stop.</li><li>the subject of a fugue.</li><li>(in a framed structure) a member, as a truss, upon which adjacent or similar members depend for support or reinforcement.</li><li>each of the combatants in a duel, as distinguished from the seconds.</li></ul><p><strong>End of Response</strong></p>