It Takes Two: Bi

Learn these prefixes that can make you think twice about the words they form: bi, di, diplo
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definitions & notes only words
  1. bilingual
    using or knowing two languages
    This study joins a heap of others suggesting that there are cognitive advantages to being bilingual.Economist (May 28, 2015)
    bi (two, twice, double) + lingua (tongue, language) + al (suffix forming adjectives)
    According to the studies, two mental advantages of being bilingual are: 1) better focus and planning of complex tasks; 2) higher ability to understand others' minds. While bilingualism is seen as a useful skill nowadays, its roots used to suggest that a speaker was lying, being hypocritical, or mixing up words from different languages.
  2. bilateral
    affecting or undertaken by two parties
    Political leaders on both sides of the border have said they want to boost bilateral trade.Economist (Aug 13, 2015)
    bi (two, twice, double) + latus (side) + al (suffix forming adjectives)
    The example sentence uses the adjective in a figurative way. A definition that connects more literally to the roots is "having identical parts on each side of an axis"--this can describe the symmetry between two sides of an object or organism, such as a plane's wings or a human's ears.
  3. bipartisan
    supported by both sides
    Criminal justice reform has attracted some bipartisan support in the usually divided Congress.Reuters (Sep 22, 2015)
    bi (two, twice, double) + parte (part, party) + an (suffix forming adjectives)
    In American politics, the adjective usually refers to agreement between Democrats and Republicans. But a partisan can be any enthusiastic supporter of a person, party, cause, or activity, and in some cases, a warlike mentality is suggested (a partisan can also be "a pike with a long tapering blade with lateral projections").
  4. bicameral
    composed of two legislative bodies
    If Congress is pleased with itself for reaching a bipartisan, bicameral deal, it’s probably time to adjust its expectations and aim a little higher.MSNBC (Dec 10, 2014)
    bi (two, twice, double) + camera (chamber) + al (suffix forming adjectives)
    In American politics, the adjective usually refers to Congress, which is composed of both the House of Representatives and the Senate. In anatomy, the adjective can describe a fish's heart, while mammals' hearts, which are divided into four chambers, are quadricameral.
  5. bifurcated
    divided into or made up of two parts
    And I think that’s why life has begun to feel so disjointed and different and bifurcated and uncertain.Forbes (Mar 1, 2013)
    bi (two, twice, double) + furca (fork) + ate (suffix forming verbs)
    As the roots show, the word originated as a verb, but it is often used as a participial adjective to describe something that has been divided into two parts. As the example sentence suggests, it usually carries a negative tone of conflict or disagreement (in the past, a fork was a weapon or a stake of the gallows).
  6. bisect
    cut in half or cut in two
    Anyway, once the games begin, every pitch is bisected and dissected; they parse out every last detail of every four-seam fastball.Washington Post (Oct 18, 2015)
    bi (two, twice, double) + secare (to cut)
    "Bisect," "dissect," and "parse" are nearly synonymous verbs. "Dis" is a prefix that means "apart" but it is related to the Latin words "bis" which means "twice" and "duo" which means "two." "Parse" comes from the Old French plural of "part" and usually refers to the grammatical analysis of the parts of a sentence.
  7. bipolar
    of or relating to manic depressive illness
    Bipolar disorder, also known as manic-depressive illness, leads to dramatic mood swings or shifts in energy and activity levels.US News (Sep 18, 2015)
    bi (two, twice, double) + polus (an end of an axis) + ar (suffix forming adjectives)
    Geographically, the earth can be described as bipolar, because it has a North and South Pole. Anything with two extreme points or two tendencies or characteristics that are directly opposite can also be described as bipolar. But nowadays, the adjective is most commonly used to describe people suffering from a mental disorder.
  8. bigamy
    having two spouses at the same time
    Bigamy and polygamy are illegal under both federal and Montana state law.Reuters (Jul 3, 2015)
    bi (two, twice, double) + gamos (marrying) + y (suffix forming abstract or collective nouns)
    As the example sentence suggests, bigamy and polygamy are often seen as equally illegal. But a serial monogamist can also be considered a polygamist (since he marries often and creates many children and households in need of support), but he is not guilty of bigamy or polygyny, which is marriage to two or more women at the same time.
  9. binoculars
    an optical instrument for simultaneous use by both eyes
    No need for telescopes or even binoculars, as the individual streaks of light can appear over large spans of the overhead sky.National Geographic (Oct 7, 2015)
    bi (two, twice, double) + oculus (eye) + ar (suffix forming adjectives)
    As the roots show, the word originated as an adjective to describe something with two eyes or that requires the use of two eyes. Before the addition of the "s" turned it into a noun, the optical instrument was called "binocular glass" or "binocle."
  10. biennial
    occurring every second year
    It found that younger women through age 54 benefit more from annual screening than biennial screening.Reuters (Oct 20, 2015)
    bi (two, twice, double) + annus (year) + al (suffix forming adjectives)
    Although the roots of "biennial" and "biannual" are the same, their meanings are not. Something that is biannual occurs twice a year, while something that's biennial occurs every two years. In botany, a biennial is a plant that lasts two seasons, unlike a perennial, which can last several seasons and often for more than two years.

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