What ≡ means
Gauss introduced it for congruence in 1801.
Carl Friedrich Gauss used ≡ in Disquisitiones Arithmeticae, his 1801 book on number theory, to write congruences compactly, for example 17 ≡ 2 (mod 5). Later writers reused it for identities that hold for every value, for logical equivalence and for definitions.
Formal notation; the field or textbook fixes its reading.
Don't read every ≡ as plain equals.
Part of the collection
What it means when someone sends it to you
3 readingsA and b leave the same remainder when divided by m.
Don't confuse it with
4
Equals Sign
Plain equality; it says nothing about remainders, identities or definitions.
Approximately Equal To
Congruent figures in geometry; a wavy line sits on top of two bars.
Trigram For Heaven
Three bars often used as the hamburger menu icon; ≡ is the math identity sign.
Strictly Equivalent To
Four bars instead of three; it means strictly equivalent.
Related characters
2
Combination ideas
317 and 2 leave the same remainder when divided by 5.
a and b differ by a multiple of n.
Three bars standing in for a hamburger menu icon.
Questions 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
26
=Equals Sign
🟰Heavy Equals Sign
≠Not Equal To
⇔Left Right Double Arrow
%Percent Sign
≌All Equal To
≣Strictly Equivalent To
⧥Identical To And Slanted Parallel
⧦Gleich Stark
⩦Equals Sign With Dot Below
⩧Identical With Dot Above
⩨Triple Horizontal Bar With Double Vertical Stroke
⩩Triple Horizontal Bar With Triple Vertical Stroke
⩭Congruent With Dot Above⩵Two Consecutive Equals Signs⩶Three Consecutive Equals Signs
⩷Equals Sign With Two Dots Above And Two Dots Below
⩸Equivalent With Four Dots Above𖭃Pahawh Hmong Sign Ib Yam
≟Questioned Equal To
≢Not Identical To
‴Triple Prime
⇚Leftwards Triple Arrow
⇛Rightwards Triple Arrow
+Plus Sign
<Less-Than SignCollections with ≡
2
How to type or find ≡
- Search it as
- triple bar · three line equals · equiv · congruent modulo · mod · identically equal
- Shows up in
- Anything that takes text · its shape is whatever your font draws
Windows (Word)
Windows
HTML
≡CSS
\2261LaTeX
Type
\equiv in math mode.Codes and encoding1 code points
HTML decimal
≡
HTML hex
≡
CSS content
content: "\2261";
Each escape is closed by the next backslash; a trailing space is needed before a literal hex digit.
URL encoded
%E2%89%A1
1
On screen
1
Code points
1
JS .length
3
UTF-8 bytes
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.