Chemistry

• n-, a lowercase prefix in chemistry denoting the straight-chain form of an open-chain compound in contrast to its branched isomer
• N-, an uppercase prefix in chemistry denoting that the substituent is bonded to the nitrogen, as in amines

Mathematics, science and technology

The italicized letter n is used in mathematics to denote an arbitrary number (usually a non-negative integer).

• n-ary associativity
• n-ary code
• n-ary group
• n-back
• n-body problem
• n-category
• n-category number
• n-connected space
• n-curve
• n-dimensional space
• n-dimensional sequential move puzzle
• n-electron valence state perturbation theory (NEVPT)
• n-entity
• n-flake
• n-gram
• n-group
• n-monoid
• n-player game
• n-skeleton
• n-slit interferometer
• n-slit interferometric equation
• n-sphere
• n-vector
• n-vector model