Trinidad and Tobago became a Republic on August 1st, 1976. The event is celebrated as a public holiday on September 24th because this is the date when the first Parliament met under the new Republican Constitution. The date was removed from the official calendar of holidays from 1999 to 2001 to make way for the Spiritual Baptist (Shouter) Liberation Day which is celebrated on March 30th. The Republic Day holiday was reinstated in 2002.
DEFINITION OF A REPUBLIC
Republic [noun]: A state or nation in which the supreme power rests in all the citizens entitled to vote (the electorate), and is exercised by representatives elected, directly or indirectly, by them, and responsible to them.
Source: Webster's New Twentieth Century Dictionary of the English Language Unabridged 2nd ed., 1973.