Order in mathematics may refer to:
Set theory Total order and partial order, a binary relation generalizing the usual ordering of numbers and of words in a dictionary Ordered set Order in Ramsey theory, uniform structures in consequence to critical set cardinality
Algebra Order (group theory), the cardinality of a group or period of an element Order of a polynomial (disambiguation) Order of a square matrix, its dimension Order (ring theory), an algebraic structure Ordered group Ordered field
Analysis Order (differential equation) or order of highest derivative, of a differential equation Leading-order terms NURBS order, a number one greater than the degree of the polynomial representation of a non-uniform rational B-spline Order of convergence, a measurement of convergence Order of derivation Order of an entire function Order of a power series, the lowest degree of its terms Ordered list, a sequence or tuple Orders of approximation in Big O notation Z-order (curve), a space-filling curve
Arithmetic Multiplicative order in modular arithmetic Order of operations Orders of magnitude, a class of scale or magnitude of any amount
Combinatorics Order in the Josephus permutation Ordered selections and partitions of the twelvefold way in combinatorics Ordered set, a bijection, cyclic order, or permutation Weak order of permutations
Fractals Complexor, or complex order in fractals Order of extension in Lakes of Wada Order of fractal dimension (Rényi dimensions) Orders of construction in the Pythagoras tree
Geometry Long-range aperiodic order, in pinwheel tiling, for instance
Graphs Graph order, the number of nodes in a graph First order and second order logic of graphs Topological ordering of directed acyclic graphs Degeneracy ordering of undirected graphs Elimination ordering of chordal graphs Order, the complexity of a structure within a graph: see haven (graph theory) and bramble (graph theory)
Logic In logic, model theory and type theory:
Zeroth-order logic First-order logic Second-order logic Higher-order logic
Order theory Order (journal), an academic journal on order theory Dense order, a total order wherein between any unequal pair of elements there is always an intervening element in the order Glossary of order theory Lexicographical order, an ordering method on sequences analogous to alphabetical order on words List of order topics, list of order theory topics Order theory, study of various binary relations known as orders Order topology, a topology of total order for totally ordered sets Ordinal numbers, numbers assigned to sets based on their set-theoretic order Partial order, often called just "order" in order theory texts, a transitive antisymmetric relation Total order, a partial order that is also total, in that either the relation or its inverse holds between any unequal elements
Statistics Order statistics First-order statistics, e.g., arithmetic mean, median, quantiles Second-order statistics, e.g., correlation, power spectrum, variance Higher-order statistics, e.g., bispectrum, kurtosis, skewness