Uni-, bi- and tri-

By kbdwil

Today in IM class we talked about three prefixes: uni-, bi- and tri-.

We talked about uni- already. Uni- usually means “one” or “all,” sort of like “everything is one.”

This prefix is used a lot in English, and also in names. Universal Studios is a good example. “Universal” comes from “universe,” which means everything that exists. The -al suffix makes it an adjective. So “universal studios” makes movies about everything!

Bi- means two. It can also appear as di- and du-. It usually means “two,” but remember that just because a word starts with “di” doesn’t mean the prefix means “two.” “Disappointing,” for example, starts with “di,” but the prefix is actually “dis-” and means something very different.

Tri- means three. There are a lot of words that use tri-, and you probably know a lot of them.

Here are some of the words we used in class today, and very brief definitions.

bi-

  • bicycle – You know what a bicycle is.
  • bipolar – Something have a high and a low point, like a planet or a personality.
  • biathlete – Someone who participates in two sports.
  • bicameral – Having two houses, as in politics. Here “camera” goes back to an old word that has to do with houses.
  • bifocals – Glasses with two different lenses for each eye. Usually for reading.
  • biannual, biennial – Used for periods of time that work in twos.
  • bigamy – Having two wives (or two husbands), usually at the same time. ;)
  • biplane – The old-fashioned airplane with two wings, one on top of the other.
  • bisect – To cut something into two.
  • dialogue – Two people talking.
  • diameter – A line that cuts a circle into two equal parts.
  • diametric – On opposite sides, like in an argument.
  • duplicate – To make a copy (a second one).
  • duplex – Anything that comes as two, like some houses.
  • duo – A pair.

tri-

  • triple play – Three outs in one play, in baseball.
  • triply – Three times as much.
  • trio – Three people, like in a musical band.
  • triplicate – Three copies.
  • tritheism – A religion that has three gods.
  • triceratops – A dinosaur with three horns.
  • trimonthly, triweekly – Periods of time that come in threes.
  • triangle – A shape with three sides.
  • tripod – A stand for a camera that has three legs.
  • triplex – Anything that comes in threes, like duplex.
  • triumvirate – A group of three rulers, working as one.
  • trilingual – Speaking three languages.

Here’s the picture of the whiteboard, so you can look at it again.

See you!

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