• Compact (newspaper), a broadsheet-quality newspaper printed in a tabloid format.
• Compact (soap opera), a 1960s British soap opera.
• a diplomatic contract or covenant among parties, sometimes known as a pact, treaty, or an interstate compact;
• Compact (cosmetics) A small, typically round case, usually containing one, two or all of the following: a mirror, pressed powder, and/or a powder puff
• Compact car
• "The Compact," a region of space inhabited by fictional aliens in The Chanur novels by C. J. Cherryh.

Mathematics

• Compact space, a topological space such that every open cover has a finite subcover. This corresponds to a closed and bounded subset of a Euclidean space
• Compactness theorem, a set of first-order sentences is satisfiable if every finite subset of it is satisfiable.
• Compact element, those elements of a partially ordered set that cannot be subsumed by a supremum of any directed set that does not already contain them
• measure of non-compactness in functional analysis
• Compact operator, a linear operator that takes bounded subsets to relatively compact subsets, in functional analysis
• Compactness measure of a shape, a numerical quantity representing the compactness (in the common sense) of a geometric shape
• Quasi-compact morphism, in algebraic geometry, a morphism of schemes for which the inverse image of any quasi-compact open set is again quasi-compact