thrive / [unvoicedth]rīv/ • v. (past throve / [unvoicedth]rōv/ or thrived; past part. thriven / ˈ[unvoicedth]rivən/ or thrived) [intr.] (of a child, animal, or plant) grow or develop well or vigorously: the new baby thrived. ∎ prosper; flourish: education groups thrive on organization | [as adj.] (thriving) a thriving economy.