Summary: The Latin root *ag* and its variant *ig* mean "do." These roots are the word origins of a fair number of English vocabulary words, including [*ag*]ent, [*ag*]ile, lit[*ig*]ate, and cast[*ig*]ate. The roots *ag* and *ig* are easily recalled through the words [*ag*]enda, or things to be "done," and nav[*ig*]ate, the "doing" or "driving" of a ship.
