# Triple bar

Identical to
Not identical to
Punctuation
apostrophe   '
brackets [ ]  ( )  { }  ⟨ ⟩
colon :
comma ,  ،
dash   –  —  ―
ellipsis   ...  . . .
exclamation mark !
full stop, period .
hyphen
hyphen-minus -
question mark ?
quotation marks ‘ ’  “ ”  ' '  " "
semicolon ;
slash, stroke, solidus /
Word dividers
interpunct ·
space
General typography
ampersand &
asterisk *
at sign @
backslash \
bullet
caret ^
dagger † ‡
degree °
ditto mark
inverted exclamation mark ¡
inverted question mark ¿
number sign, pound, hash, octothorpe #
numero sign
obelus ÷
ordinal indicator º ª
percent, per mil % ‰
plus and minus + −
basis point
pilcrow
prime
section sign §
tilde ~
underscore, understrike _
vertical bar, pipe, broken bar |    ¦
Intellectual property
service mark
Uncommon typography
asterism
hedera
index, fist
interrobang
irony punctuation
lozenge
reference mark
tie
Related
In other scripts

The triple bar, , is a symbol with multiple, context-dependent meanings. It has the appearance of a "=" sign with a third line. The triple bar character in Unicode is codepoint U+2261 identical to (HTML: &#8801; &equiv;). LaTeX \equiv corresponds to the triple bar.

In logic, it has a similar meaning to the if and only if connective, ⇔. However, in some texts ⇔ is used as a symbol in logic formulas, while ≡ is for reasoning about those formulas (as in metalogic).

In mathematics, it is sometimes used a symbol for congruence (although not the only one). Particularly, in number theory, it has the meaning of modular congruence: $a \equiv b \pmod N$ if N divides ab.

This symbol is also used when it appears in an equation which is a definition of its left-hand side, that is an equation which is not derived but instead defined.

It is also used for "identical equality" of functions; one writes $f \equiv g$ for two functions f, g if we have $f(x) = g(x)$ for all x.

In botanical nomenclature, the triple bar denotes homotypic synonyms (those based on the same type specimen), to distinguish them from heterotypic synonyms (those based on different type specimens), which are marked with an equals sign.[1]

In chemistry, the triple bar can be used to represent a triple bond between atoms. For example, HC≡CH is a common shorthand for acetylene.

If seen on websites, it can often be clicked (or touched on a touch-based device) to bring up a navigational menu, also know as the "Hamburger Icon". [2]

## References

1. ^ "Guidelines for authors" (PDF). Taxon 62 (1): 211–214. 2013.
2. ^ Cox, Norm. "The origin of the hamburger icon". Evernote.