- (logic) Joins two statements of which not both are true (nand).
- (mathematics) Such that; having the property that.
- (mathematics, of an expression) Evaluated at.
- (mathematics) absolute value, or, more generally, modulus
- |-3| = 3
- For x = (1,1), and y = (4,5), |x – y| = √([1–4]2 + [1–5]2) = 5
- |A| means the determinant of the matrix A
- (mathematics) cardinality
- (mathematics) number of connected components
- (statistics) conditional probability
- Pr(X|Y) — "The probability of X given Y"
- A tally mark.
- The number 6 can be represented as ||||||.
- Often called vertical bar, or pipe.
- (logic) Called Sheffer stroke