Michigan Compiled Laws, Chapter 205. Taxation § 205.54p

(a) “Regularly organized church or house of religious worship” means a religious organization qualified under section 501(c)(3) of the internal revenue code,26 USC 501.

(b) “Sanctuary” means only that portion of a building that is owned and occupied by a regularly organized church or house of religious worship that is used predominantly and regularly for public worship. Sanctuary includes a sanctuary to be constructed that will be owned and occupied by a regularly organized church or house of religious worship and that will be used predominantly and regularly for public worship.