means The elected or appointed head of a nation, organization, or assembly, holding the highest office and authority within it.

from From Latin 'praesidens,' the present participle of 'praesidere,' to preside or 'sit before' — literally one who sits at the front, from 'prae' (before) plus 'sedere' (to sit), a cousin of words like 'sedentary' and 'session.' It entered English through Old French in the late Middle Ages as a word for any presiding officer; only in the 18th century, when the framers of the United States needed a title for their new head of state that carried no royal whiff, did 'president' rise to mean the leader of a republic — a chairman elevated to a nation.