in rhetoric, a kind of tropes, frequent among orators and poets. There are three kinds of synecdoches. By the first, a part is taken for the whole; as the point for the sword, the roof for the house, the sails for the ship, &c. By the second, the whole is used for a part. By the third, the matter whereof the thing is made is used for the thing itself; as steel for sword, silver for money, &c. To which may be added another kind, when the species is used for the genus, or the genus for the species.

in Greek and Latin grammar, is when the ablative of a part or an adjunct of a sentence is changed into the accusative.