bi-, bin-, bino-, bis-

(Latin: two, twice, double, twofold; a number; it normally functions as a prefix)

This bi- is used before s, c, or a vowel. Don't confuse this bi- with another one which means "life".

All words except biennial referring to periods of time and prefixed by bi- are potentially ambiguous. Since bi- can be taken to mean either "twice each" or "every two", a word like "biweekly" can be understood as "twice each week" or "every two weeks".

bicentricity (s), bicentricities (pl) (nouns)
1. Having two points or places that are equally distant from the sides or outer boundaries of something.
2. The point around which something or an object rotates or revolves.
Having two heads.
biceps (s) (noun); biceps, bicepses (pl)
A muscle with two points of origin; especially, the large muscle at the front of the upper arm that flexes the elbow joint and the large muscle at the back of the thigh that flexes the knee joint.

A person's biceps is a muscle having two heads or two points of attachment.

bicipital (adjective) (not comparative)
Of or relating to the biceps of the muscles; having two heads or areas of origin.
1. Concave on both sides; as, a biconcave vertebrae or as a lens.
2. A description of a lens with two faces that are concave
bicorporal (bigh KOR puhr uhl), bicorporeal (bigh" kor POHR ee uhl) (adjective) (not comparative)
Having two distinct bodies or main parts.
bicultural (adjective), more bicultural, most bicultural
1. Of, pertaining to, or combining two cultures.
2. Relating to two distinct cultures in one nation or geographic region; for example, bicultural education.
Having or terminating in two cusps, or points, as certain teeth.

A person's bicuspids are teeth with two points; located between the incisors and the molars.

bicycle (s) (noun), bicycles (pl)
bidigitate, bidigital
Having two digits, fingers, or finger-like processes.
Capable of operating (not simultaneously) in either of two directions that are the opposite of each another.
biennial (adjective) (not comparable)
Pertaining to something that happens every two years: The family got together on a biannual basis to celebrate birthdays.

A biennial plant lives for two years and produces flowers and fruit in the second year.

Note: "biannual" means "twice a year"; which is, within the same year.