In this subchapter:
(1) "Derivative proceeding" means a civil suit in the right of a domestic corporation or, to the extent provided by Section 21.562, in the right of a foreign corporation.
(2) "Shareholder" includes:
(A) a shareholder as defined by Section 1.002;
(B) a beneficial owner whose shares are held in a voting trust or by a nominee on the beneficial owner's behalf; or
(C) two or more shareholders acting in concert under an informal or formal agreement or understanding with respect to a derivative proceeding.