1. a system of two stars that revolve around each other under their mutual gravitation;

[syn: binary star, binary, double star]

The Collaborative International Dictionary of English v.0.48:

Binary \Bi"na*ry\, a. [L. binarius, fr. bini two by two, two at a time, fr. root of bis twice; akin to E. two: cf. F. binaire.] Compounded or consisting of two things or parts; characterized by two (things). [1913 Webster] Binary arithmetic, that in which numbers are expressed according to the binary scale, or in which two figures only, 0 and 1, are used, in lieu of ten; the cipher multiplying everything by two, as in common arithmetic by ten. Thus, 1 is one; 10 is two; 11 is three; 100 is four, etc. --Davies & Peck. Binary compound (Chem.), a compound of two elements, or of an element and a compound performing the function of an element, or of two compounds performing the function of elements. Binary logarithms, a system of logarithms devised by Euler for facilitating musical calculations, in which 1 is the logarithm of 2, instead of 10, as in the common logarithms, and the modulus 1.442695 instead of .43429448. Binary measure (Mus.), measure divisible by two or four; common time. Binary nomenclature (Nat. Hist.), nomenclature in which the names designate both genus and species. Binary scale (Arith.), a uniform scale of notation whose ratio is two. Binary star (Astron.), a double star whose members have a revolution round their common center of gravity. Binary theory (Chem.), the theory that all chemical compounds consist of two constituents of opposite and unlike qualities. [1913 Webster]WordNet (r) 3.0 (2006):

binary star n 1: a system of two stars that revolve around each other under their mutual gravitation [syn: binary star, binary, double star]