◊

See also: ⋄ [U+22C4 DIAMOND OPERATOR], ◇ [U+25C7 WHITE DIAMOND], and ♢ [U+2662 WHITE DIAMOND SUIT]

◊ U+25CA, ◊ LOZENGE ← ◉ [U+25C9] Geometric Shapes ○ → [U+25CB]

⧫ U+29EB, ⧫ BLACK LOZENGE ← ⧪ [U+29EA] Miscellaneous Mathematical Symbols-B ⧬ → [U+29EC]

Translingual

Etymology

The use of this notation in modal logic was developed by C.I. Lewis.

Symbol

◊

1. (logic, unfilled) possibility, possible, possibly

   ∀𝑥□𝐹𝑥 → □∀𝑥𝐹𝑥 ⇔ ◊∃𝑥𝐹𝑥 → ∃𝑥◊𝐹𝑥 ― Barcan formula

2. (set theory) the diamond principle
3. (calculator) subtotal
4. (traffic) high-occupancy vehicle lane, bus lane
5. (botany, unfilled) sex unknown

Synonyms

• (modal operator denoting possibility): M

See also

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