Perpendicular (⊥) in LaTeX
\perp prints the perpendicular symbol, meaning two lines or vectors meet at a right angle (and, in probability, statistical independence). \parallel is its companion for parallel lines.
LaTeX command
\perpNot the symbol you meant? Draw it to find the command →
\perp renders the up-tack used to say two lines, segments or vectors are perpendicular, as in AB \perp CD. It is a relation symbol, so LaTeX spaces it accordingly. It needs no package and renders in KaTeX. The same glyph appears in logic as the bottom (false) symbol and, doubled, as an informal sign for statistical independence.
Its natural pair is \parallel, the double vertical bar meaning two lines are parallel; use \nparallel (from amssymb) for not parallel. To mark the actual right angle at a vertex you usually state the measure with 90^{\circ} or use \angle, since \perp expresses the relation rather than labelling the angle.
Take care to distinguish \perp from \bot. They print the same up-tack, but \bot is intended as the logical false or bottom element while \perp is the perpendicular relation with relational spacing. Use whichever matches your meaning so the spacing comes out right.
Other forms
\parallelparallel (∥)Examples
$AB \perp CD$two perpendicular lines
$\vec{u} \perp \vec{v} \iff \vec{u} \cdot \vec{v} = 0$orthogonal vectors
$\ell_1 \parallel \ell_2$parallel lines, the companion relation
$X \perp Y$independence of random variables (informal)
Tips and common mistakes
\perpis a relation and needs no package; it renders directly in KaTeX.- Use
\parallelfor the parallel relation and\nparallel(amssymb) for not parallel. \perpand\botlook identical but differ in meaning and spacing:\perpis the perpendicular relation,\botthe logical false or bottom.\perpexpresses a relation; to label the actual right angle at a vertex use 90^{\circ} or\angle.- For a clearer independence sign,
\perp\!\!\!\perpuses negative thin spaces to pull two tacks together, or define an\independentmacro in your preamble.
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Convert your maths to LaTeX →FAQ
How do I write the perpendicular symbol in LaTeX?
Use , for example . It needs no package and works in KaTeX.
What is the command for parallel lines?
\parallel, as in . Use \nparallel (from amssymb) for not parallel.
What is the difference between \perp and \bot?
They render the same up-tack, but \perp is the perpendicular relation with relational spacing, while \bot is the logical bottom or false symbol. Choose by meaning.