Leader
A leader was an individual who lead or influenced others. Authority was granted to leaders by those they lead or by their superiors. The capacity of being a leader was called leadership.

On Neural, according to Nona, males sought out Kahn-ut-tu females, like her, for through them they became great leaders. ()

For the sleeper ships of 20th century Earth, it was the standard practice for the leader to be revived first. This would give them the time to make a decision on whether the conditions warranted the revival of the others. ()

When the transporter duplicated Captain James T. Kirk in 2266, Lieutenant Commander Spock had the rare opportunity of appraising the Human mind, or the roles of good and evil in a man. An exceptional leader, as noted by Spock, was strong because of their evil, or negative, side. When properly controlled and disciplined, this side, with its hostility, lust, and violence, gave strength to a leader. With the negative side removed, the good, or positive, side of Kirk found the ability. ()

In 2268, upon learning that Captain James T. Kirk wished to speak with those in charge of the Eymorg,  asked the question, "In charge?", indicating that she did not understand the meaning of this phrase. In explanation, Kirk replied, "Yes, the organizers, the managers. The leader of your people." ()

In 2364, Ligonian custom made it clear that a visiting leader became an honored guest. ()

In 2366, Jean-Luc Picard noted to Data that excessive honesty could be disastrous, particularly in a commander, as advertising one's limitations to a crew could damage credibility as a leader. ()

In a few cultures, leader was the title for an individual in charge.

In 3189, Leader Pav was the head of the Trillian government on Trill. ()

See also 
 Business leader
 Community leader
 Mission leader
 Priestess leader
 Spiritual leader
 Team leader
 Unit leader

Occupations
Titles