As used in this section and sections 492a to 497:

    (a) "Derivative proceeding" means a civil suit in the right of a domestic corporation or a foreign corporation that is authorized to or does transact business in this state.

    (b) "Shareholder" means a record or beneficial owner of shares and includes a beneficial owner whose shares are held in a voting trust or held by a nominee on the owner's behalf.

    (c) "Disinterested director" means a director who is not a party to a derivative proceeding, or a director who is a party if the corporation demonstrates that the claim asserted against the director is frivolous or insubstantial.