White, black and large circles
In Unicode names, "white" means an outline and "black" means filled. So ○ is the white circle (U+25CB), ● is the black circle, ◯ is a large outline circle and ⬤ a large filled one. ◎ is called a bullseye, ◉ a fisheye, and ◌ a dotted circle. The small ◦ (white bullet) and ⚬ work well as sub-bullets under a main • bullet.
Some circles have special jobs. ∘ (ring operator) means function composition in math, as in f ∘ g. 〇 is the ideographic number zero used in Chinese and Japanese numbers, not a shape. In Japan and Korea, a circle ○ marks a correct answer on tests and forms, while × marks a wrong one.
Ratings, status labels and more
Filled and empty circles make simple ratings and progress indicators: ●●●○○ for three out of five, or ◔ ◑ ◕ ● for a quarter, half, three quarters and done. Colored emoji circles are handy status labels: 🟢 online or done, 🟡 in progress, 🔴 blocked or live.
Circled operators come from math: ⊕ often means exclusive or (XOR) or a direct sum, and ⊗ a tensor product. For small round dots and bullets, visit the dot symbol page, and for moon-like half circles, the moon symbol page. Circled letters such as Ⓐ ⓑ are on the letter symbols page.
How to type circle symbols
On Windows, hold Alt and type 9 on the number pad for ○, or 7 for the bullet •. There is no Alt code for ●, so copy it or open the emoji panel with Win + .. On a Mac, open the Character Viewer with Control + Command + Space and search "circle".
In Microsoft Word, type 25CB (○) or 25CF (●) and press Alt + X. In HTML, use ○ for ○ and ● for ●. In LaTeX, \circ gives ∘, \bigcirc gives ◯, and \oplus and \otimes give ⊕ and ⊗. On phones, search "circle" in the emoji keyboard for ⚪︎ ⚫︎ 🔴 🔵 and the rest.