The tee (⊤, \top in LaTeX), also called down tack (as opposed to the up tack) or verum, is a symbol used to represent:

• The top element in lattice theory.
• The truth value of being true in logic, or a sentence (e.g., formula in propositional calculus) which is unconditionally true.^[1][2][3] By definition, every tautology is logically equivalent to the verum.
• The top type in type theory.
• Mixed radix encoding in the APL programming language.
• A lowered phonic in the International Phonetic Alphabet and phonetics. In this usage, it is usually written under the primary IPA symbol.

A similar-looking superscript T may be used to mean the transpose of a matrix.

Encoding

In Unicode, the tee character is encoded as U+22A4 ⊤ DOWN TACK (⊤, ⊤).^[4] The symbol is encoded in LaTeX as \top.

A large variant is encoded as U+27D9 ⟙ LARGE DOWN TACK in the Unicode block Miscellaneous Mathematical Symbols-A.