| A | B |
|---|
| unicellular | having only one cell |
| unicorn | a horse-like fabled animal that has one horn growing out of the middle of its forehead |
| unicycle | a one-wheeled vehicle on which the rider sits and pedals |
| unidirectional | moving in only one direction |
| unify | to join together into one group |
| unilateral | one sided |
| unique | one of a kind; unusual or rare |
| unison | an instance of saying the same words or sounds at the same time; a group that sounds like one |
| unit | one group |
| unitard | a one-piece leotard and tights combination |
| bilingual | a person who speaks both Spanish and English |
| bicuspid | a two-pointed tooth located in the side of the jaw |
| bicycle | a vehicle with two wheels |
| biennial | happening every two years |
| bifocals | eyeglasses with lenses that have two different sections- one for seeing up close, and one for seeing far away |
| bimonthly | happening every two months |
| biped | a two-footed created |
| biplane | an airplane with two pairs of wings |
| biweekly | happening every two weeks |
