What ⦵ means
It marks the reference value of a quantity.
The Plimsoll mark appears as a superscript beside enthalpy, entropy, Gibbs energy, or electrode potential to mark the value in the standard state. Books may instead use a degree sign, superscript zero, or stroked lowercase o.
Why is ⦵ called the Plimsoll mark in chemistry?
Its name recalls a ship’s load-line safety mark.
Britain’s 19th-century Plimsoll line marked safe ship loading. Named for reformer Samuel Plimsoll, the line became compulsory in 1876; chemists reused its shape for the standard state.
The traditional chemistry mark has a smaller circle and a longer bar than ⦵.
Technical, puzzling in chat.
Not a general no sign.
Part of the collection
Don't confuse it with
3
Related characters
1
Combination ideas
4Questions people ask
1Why does ⦵ show as a box on some devices?
Because that device's fonts have no glyph for it. The character is still correct and still copies correctly — the box is a missing glyph, not a broken character.
More like this
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How to type or find ⦵
- Also called
- Plimsoll mark
- Search it as
- plimsoll · standard state · circled minus · theta
- Shows up in
- Anything that takes text · its shape is whatever your font draws
⦵\29B5Codes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.