Prefixes in Geometry
There are many new words you must know to be able to describe shapes and a solid luckily there is a
pattern to the way these words are used.
Meaning
Three
3
Prefix
Shape
Tri
Triangle
Solid
Star
Quadrilateral
Four
4
Quad
Four
4
Tetra
Tetragon
(rarely used)
Tetrahedron
Five
5
Penta
Pentagon
Pentahedron
Six
6
Hexa
Hexagon
Seven
7
Hepta
Eight
8
Octa
Nine
9
Nona
Ten
10
Twelve
12
Pentagram
Hexagram
Heptahedron
Heptagram
Octahedron
Octagram
Nonagon
Nonahedron
Nonagram
Deca
Decagon
Decahedron
Decagram
Dodeca
Dodecagon
Dodecahedron
Dodecagram
∗
Heptagon
Hexahedron
Cube
Tetragram
Octagon
Hexadecagram
Sixteen
16
Hexadeca
Twenty
20
Icosa
100
Hecto
One hundred
Many
Poly
Icosagon
Icosahedron
Icosagram
hectogram
Polygon
Polyhedron
Look at the table above. What do you think the suffix gon mean?
Plane Shape (angle) [Greek -g non, from neuter of g nos, angled, from g ni , angle.]
Look at the table above .What do you think the suffix hedron mean?
Solid Shape (face) [New Latin, from Greek -edron, neuter of -edros, -sided, from hedr , face.]
Why do you think there are two different prefixes for four?
Quad and latus are Latin. Quad means four and latus means sides. Quadrilateral literally means
‘four sides’. Tetra is the Greek word for four; Tetragon literally means ‘four angles’. This means
that a quadrilateral is the only shape named for its sides rather than its angles.
∗
Septa is often used for seven. Hepta is from the Greek and Septa from Latin)
Hannah Smith
Geometry
Page 1
11/14/10
Literacy
Using a Dictionary and the information on the front of this sheet to identify the number prefix and to
find the meanings of the following words:
Word
Number
Meaning
biannual
2
Twice a year.
biennial
2
Every two years.
bilingual
2
Speaks two languages.
110
decilitre
One tenth of a litre. 100ml.
110
decimate
Literally to kill one tenth of an army.
hectopascal
100
One hundred Pascals. A unit of pressure.
hectostere
100
One hundred stere. A measure of solidity, containing one
hundred cubic meters.
hexameter
6
A term from poetry. A line of verse consisting of six metrical
feet.
hexapod
6
A six-legged arthropod. An insect.
icosander
20
In botany, a plant having twenty or more stamens inserted in the
calyx.
nonagenarian
90
A person in their Nineties. E.g. someone who is 92 years old.
nonagesimal
90
Ninetieth
octave
8
Music. A group of eight notes.
octogenarian
80
A person in their eighties.
Hannah Smith
Geometry
Page 2
22 October 2004
Literacy
Word
Number
Meaning
pentacle
5
A five pointed star.
pentathlon
5
An athletic event made up of five parts, usually the 200 metre
and 1,500 metre runs, the long jump, and the discus and javelin
throws.
quadrennial
4
Occurring every four years. eg the Olympic Games.
quadruple
4
To multiply or be multiplied by four.
quadruplet
4
One of four babies born in a single birth.
septuagenarian
70
A person in their seventies.
septuple
7
To multiply or be multiplied by seven.
sextuple
6
To multiply or be multiplied by six.
sextuplet
6
One of six babies born in a single birth.
tetralogy
4
A collection of four books.
tetrameter
4
Poetry. A line of verse consisting of four metrical feet.
triennial
3
Occurring every three years.
trilogy
3
A collection of three books.
triplicate
3
Three copies
Hannah Smith
Geometry
Page 3
22 October 2004
Literacy
Some of our words
for numbers come from the Latin
language and some come from the Ancient
Greek language. The Ancient Greeks were very
interested in mathematics, particular in Geometry,
which is why most of our names for the shapes and
solids are derived from Ancient Greek words.
Greek
Latin
Meaning
Tetra
Quatra
4
Icosa
Hepta
viginti
Centum
20
100
The Latin word for 100 was Centum and the numeral
that the Roman’s used to represent 100 was a C.
Here are some examples of words that use the Latin
prefix Cent
Centenarian
someone who is at least 100 years old
Centennial
occurring every 100 years
Centurion
a officer in the Roman Army who
commanded 100 men. (A unit of 100
men was called a Century.
Task
Find two other English words that use the prefix Cent.
centenary, centesimal, centigrade, centilitre,
centimetre, centipede,
Research:
Find out why September is the
ninth month of the year and not
the seventh month of the year
as its name suggests?
Pope Gregory XIII’s calendar reforms
Task
Write down the words on page 1 that come from Latin.
Hint: there are only two.
Triangle
Quadrilateral
____________________________________________
Hannah Smith
Geometry
Page 4
22 October 2004
Literacy