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An operator and a letter that resemble each other closely enough to be substituted constantly.
The set-membership sign says a thing belongs to a set and sits between two expressions. Epsilon is a Greek letter naming a quantity, most famously the arbitrarily small tolerance in the epsilon–delta definition of a limit. They are distinct characters; the membership sign is drawn with a longer, straighter middle stroke and is used as a relation rather than as a value.
Drawn almost identically to the Greek letter epsilon. This sign asserts a relation; the letter names a quantity.
| Element-of sign | Epsilon | |
|---|---|---|
| What it is | A relation: belongs to | A letter naming a quantity |
| Where it sits | Between an element and a set | In place of a value |
| Code point | U+2208 ELEMENT OF | U+03B5 GREEK SMALL LETTER EPSILON |
| Best known from | Set-theory notation | The epsilon–delta definition of a limit |
| Relationship (from Symbolwise's records) | Commonly confused with Epsilon — Drawn almost identically to the Greek letter epsilon. This sign asserts a relation; the letter names a quantity. | Commonly confused with Element-of sign — The set-membership sign is a distinct character from this letter, and the resemblance is close enough that the two are routinely substituted for one another. |
Unicode Code Chart: Mathematical Operators (U+2200–U+22FF)
The Unicode Consortium · retrieved 2026-07-30
Authoritative for the character's code point, name and block only. Unicode assigns identity; it does not define what a symbol means in use.
Wikipedia · retrieved 2026-07-31
Tertiary reference. Used for the widely-agreed uses of the letter across fields and for its history. Not used to assert that any one use is the letter's definitive meaning — no body defines that, and the record says so.
Wikipedia · retrieved 2026-07-31
Tertiary reference. Used for what the notation means in ordinary mathematical practice and for attribution of its introduction, not for a claim that any body defines it.
Both are drawn as one continuous decorative stroke with a closed loop and a tail that crosses back over itself, which is why a description of the shape alone reaches both. The clef is far taller, spans a stave, and its spiral encircles one specific line — that encircled line is the note G, and it is the only reason the shape is drawn where it is.
The ampersand is a ligature of the Latin word et, still visible in some italic forms where the e and the t can be picked out. The Tironian et is a separate mark descending from a Roman shorthand, shaped like a small seven, and it is in daily public use in Ireland as the written form of 'agus'. A reader who knows only the ampersand takes the other for a numeral, which on a bilingual road sign produces a confidently wrong place name.
As punctuation the asterisk points at a footnote or marks a required field. In a filename pattern typed at a shell it matches any run of characters, including none — and the shell expands it against real filenames before the command runs, so the command never sees the pattern at all. That expansion is the part people are surprised by.
A single C in a circle asserts copyright. Two C shapes mark a Creative Commons licence — which grants specific permissions while the creator keeps their copyright. A CC badge does not put a work in the public domain, and it does not tell you what you may do on its own: the condition marks beside it carry the terms.