What is Quae Est Eadem?

Legal Definition
Pleading. Which is the same.

2. When the defendant in trespass justifies, that the trespass justified in the plea is the same as that complained of in the declaration; this clause is called quae est eadem. Gould. Pl. c. 3, s. 79, 80.

3. The form is as follows: "which are the same assaullting, heating and ill-treating, the said John, in the said declaration mentioned, and whereof the said John hath above thereof complained against the said James." Vide 1 Saund. 14, 208, n. 2; 2 Id. 5 a, n. 3; Archb. Civ. Pl. 217.
-- Bouviers Law Dictionary
Legal Definition
Lat. Which is the same. Words used for alleging that the trespass or other fact mentioned in the plea is the same as that laid in the declaration, where, from the circumstances, there is an apparent difference between the two. 1 Chit PI. 582.
-- Black's Law Dictionary
Legal Definition
Which is the same matter.
-- Ballentine's Law Dictionary