Meaning
The kanji 営 on a square button, taken from the Japanese word for doing business. On signs it means open for business: the shop is trading now.
Small businesses use it to announce opening hours or a grand opening, and friends use it jokingly for being open to plans: “Bakery 🈺 from 7 am, fresh bread waiting” It pairs with 🏪 or 🕖. There is no matching closed button, so a plain word works better on days off.