# order

In mathematics, the term 'order' has many different
meanings. Among these are: (1) the sequence in which
a set of objects or numbers is placed; (2) the number of elements in
a set; (3) the number of times a shape can be fitted back onto its own
outline during a complete turn (**order of symmetry**);
(4) the highest order power in a
one-variable polynomial (**order
of a polynomial**, also known as its **degree**);
(5) the type of curve described by such a polynomial (**order
of a curve**).

In biology, order is a taxonomic rank below class and above family. Order names are printed in Roman (ordinary) letters, and begin with a capital letter. Among animals, the names of most orders end in -a, such as Anura (frogs and toads) and Chiroptera (bats), although bird orders end in -iformes, such as Columbiformes (pigeons) and Stringiformes (owls). In plants, order names generally end in -ales, such as Rosales (roses).