bi-

Prefix

bi-

1. Two in number.
   • biarticular
   • biaxial
2. Having or possessing two of the root word's quality.
   • biangular
   • biantheriferous
3. Both: referring to two as a set.
   • biacetabular
   • biallelic
4. Being different in two ways with respect to the root.
   • biadjoint
   • biaffine
5. Forked, divided by two, halved; (chemistry, proscribed) half
   • bifurcate
   • bicapitate
6. Double, twofold.
   • bialgebroid
   • bifarious
7. Bisexual, relating to bisexuality.
   • bicentric
   • biphobia
8. Bilateral, on both sides of the body.
   • biconcave
   • biballism
9. Twice.
   • biannual
   • biannual
10. Every two; a rate of once every two.
    • biannual
    • bicentennial
11. A pair of; composed of two.
    • bibrow
    • bicomplex
12. Used for the digit two to form systematic element names of elements whose existence has been predicted, and which have not yet been given a trivial name.
    • un- (“1”) + bi- (“2”) + un- (“1”) + -ium (element suffix) → unbiunium (“element 121”)

    Synonyms:

    di-, duo-