主演（しゅえん）：starring; playing the leading part

主：chief; lord; main thing; master; principal

on-reading シュ、シュウ、ス. kun-reading あるじ、おも、ぬし.

主（あるじ）：1. head (of a household); proprietor (of a store); proprietress; landlord; landlady; master (of a servant) (abbreviation)

主（おも）：1. chief; main; principal; important 2. main secondary or supporting role (in kyogen) (abbreviation)

主（ぬし）：1. head (of a household); leader; master 2. owner; proprietor; proprietress 3. subject (of a rumor, etc); doer (of a deed) 4. guardian spirit 5. husband (pronoun) 6. you (familiar language)

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演：already covered here.