Meaning
A black square of medium size, smaller than ⬛ but bigger than ◾. It means black and is mostly used as a solid, modern bullet or block.
It suits minimalist lists, menus and section headings where a round bullet feels too soft: “◼️ Location ◼️ Price ◼️ Opening hours” Without the emoji variation it may show as a plain text square, which some people actually prefer for a clean look.