Ablative n. (Gram.) The ablative case. ablative absolute, a construction in Latin, in which a noun in the ablative case has a participle (either expressed or implied), agreeing with it in gender, number, and case, both words forming a clause by themselves and being unconnected, grammatically, with the rest of the sentence; as, Tarquinio regnante, Pythagoras venit, i. e., Tarquinius reigning, Pythagoras came.