bi ‧ na ‧ ry /ˈbaɪnəri/ BrE AmE adjective
[ Date: 1400-1500 ; Language: Late Latin ; Origin: binarius , from Latin bini 'two by two' ]
1 . the binary system a system of counting, used in computers, in which only the numbers 0 and 1 are used
2 . consisting of two parts SYN double :
a binary star system