noun
billboard; large signboard
Refers to a physically large outdoor sign, typically used for advertising or public notices.
駅前に新しい大看板が設置された。
A new large billboard was installed in front of the station.
noun
star performer; leading attraction;
Figurative use from the idea of a big signboard advertising a star. Refers to a top-billed actor, singer, or other performer who draws audiences.
彼は今や劇団の大看板だ。
He is now the star performer of the theater company.