dual dual /ˈduːl/

adjective

1. () Consisting of or involving two parts or components usually in pairs  ( duple , dual , double )
   consisting of or involving two parts or components usually in pairs
    An egg with a double yolk
   an egg with a double yolk
    A double (binary) star
   a double (binary) star
    Double doors
   double doors
    Dual controls for pilot and copilot
   dual controls for pilot and copilot
    Duple (or double) time consists of two (or a multiple of two) beats to a measure
   duple (or double) time consists of two (or a multiple of two) beats to a measure
   
2. A grammatical number category referring to two items or units as opposed to one item (singular) or more than two items (plural)  ( dual )
   a grammatical number category referring to two items or units as opposed to one item (singular) or more than two items (plural)
    Ancient Greek had the dual form but it has merged with the plural form in modern Greek
   ancient Greek had the dual form but it has merged with the plural form in modern Greek
   
3. Having more than one decidedly dissimilar aspects or qualities  ( dual , three-fold , threefold , double , treble , two-fold , twofold , trifold )
   having more than one decidedly dissimilar aspects or qualities
    A double (or dual) role for an actor
   a double (or dual) role for an actor
    The office of a clergyman is twofold; public preaching and private influence
   the office of a clergyman is twofold; public preaching and private influence
    Every episode has its double and treble meaning
   every episode has its double and treble meaning