Meaning

noun one of three equal parts of a divisible whole

noun the fielding position of the player on a baseball team who is stationed near the third of the bases in the infield (counting counterclockwise from home plate)

noun following the second position in an ordering or series

originPIE word *tréyes From Middle English thirde, thridde, from Old English þridda, from Proto-Germanic *þridjô, from Pre-Germanic *tretyós, a remodeling of Proto-Indo-European *tr̥tyós.

Etymology from Wiktionary, CC BY-SA 3.0