Grade by Grade
B. Foundations of Language · Spelling, Grammar and Punctuation

Greek Word Parts in Science and Math

B2.1 B2.2 A3.1About 45 minutes
Learning goals
  • I can tell the meaning of Greek word parts like hydro, chron, logy, astro, cycl, poly, gon, dia, peri and sphere.
  • I can use Greek word parts to read and spell math and science words.
  • I can use Greek spelling clues: ph for /f/, ch for /k/, and y for /i/.
  • I can explain how the parts of a word add up to its meaning.

Words to know

Greek
The language of ancient Greece. Many science and math words come from Greek.
combining form
A word part, often Greek, that joins with other parts to make a word, like bio + logy.
-logy
A Greek word part that means the study of.
polygon
A closed shape with many straight sides.

Remember from Grade 4

In Grade 4 you learned Greek word parts like tele (far), micro (small), scope (look at), phon (sound), graph (write), photo (light), auto (self), bio (life), geo (earth) and therm (heat). You learned the Greek spelling clues: ph says /f/, ch can say /k/, and y in the middle of a word can say /i/.

Scientists and mathematicians love Greek word parts. Once you know them, words like hexagon and hydroelectric stop being scary.

Greek partMeaningExamples
hydrowaterhydrant, dehydrated, hydroelectric
chrontimechronological, synchronize
-logythe study ofbiology, geology, zoology
astro / asterstarastronaut, astronomy, asterisk
cyclcircle, wheelbicycle, recycle, cycle, cyclone
sphereballsphere, hemisphere, atmosphere
polymanypolygon
gonanglepolygon, pentagon, hexagon, octagon
diathrough, acrossdiameter, diagonal, diagram
periaroundperimeter, periscope
Grade 5 Greek word parts

Greek in your math class

  • polygon: poly (many) + gon (angle). A shape with many angles (and many sides).
  • pentagon (5 angles), hexagon (6 angles), octagon (8 angles). A stop sign is an octagon.
  • perimeter: peri (around) + meter (measure). The distance around a shape.
  • diameter: dia (across) + meter (measure). The distance across a circle, through the centre.

Greek in your science class

  • hydroelectric: electricity made using moving water. In Ontario, many people even call electricity hydro, as in the hydro bill!
  • atmosphere: the layer of air that surrounds Earth like a ball-shaped blanket.
  • hemisphere: hemi (half) + sphere (ball). Half of Earth, like the Northern Hemisphere, where Canada is.
  • astronomy: the study of stars, planets and space.
perimeterperi (around) + meter (measure)4 cm sidesdiameterthrough the centrediameterdia (across) + meter (measure)the distance around
Perimeter is the distance around a shape (here 4 + 4 + 4 + 4 = 16 cm); diameter is the distance across a circle, through the centre. Not to scale.
NorthernHemisphereSouthernHemisphereequatorhemi = halfsphere = ballCanada is in theNorthern Hemisphere.
hemi (half) + sphere (ball) = hemisphere: half of Earth. The equator divides Earth into the Northern and Southern Hemispheres. Not to scale.
Worked example

Let's figure out *chronological order*

Your teacher asks you to put events from your life in chronological order. What does that mean?

  1. Find the Greek parts: chron + o + logical.
  2. chron = time. logical comes from logic, a sensible way of thinking (and -logy).
  3. Put it together: an order that makes sense by time.

Chronological order means in time order: first to last, like a timeline.

Worked example

Let's spell /SIGH-kloan/

Spell the name of a huge storm with winds spinning in a circle.

  1. The meaning circle points to the Greek part cycl.
  2. In Greek words, y often says /i/ or /eye/, and c before y says /s/.
  3. Add the ending -one: cycl + one = cyclone.

cyclone (c-y-c-l-o-n-e).

Just for fun

Hippopotamus is Greek for river horse: hippo (horse) + potamos (river). Ancient Greeks clearly never tried to ride one.

Meter or metre?

A meter is a tool that measures (thermometer, speedometer). A metre is a unit of length in Canadian spelling (kilometre, centimetre). In math words like perimeter and diameter, the Greek part is spelled -meter because they name a measurement, not the unit.

Hands-on activity

Greek word building blocks

You need: 16 small cards or paper squares, and a pencil.

  1. Write one word part on each card: hydro, chron, bio, geo, zoo, astro, cycl, bi, re, poly, gon, penta, hexa, octa, peri, meter.
  2. Lay them out. How many real words can you build by putting two or three cards together? (bi + cycl + e = bicycle, penta + gon = pentagon, zoo + logy... make a card for logy too!) Note: bi and re are Latin prefixes, not Greek, but they often join Greek parts, as in bicycle and recycle.
  3. Write each word and its meaning.
  4. Hunt around your home for an object whose name has a Greek part (a thermometer, a bicycle, a globe map of a hemisphere).
  5. Draw and label a pentagon, a hexagon and an octagon. Count the angles on each to check the names.

Your turn

1

What does hydro mean? Name a word with it.

2

What is zoology?

3

How many angles does a hexagon have? How many sides?

4

What is the perimeter of a rectangle 5 m long and 3 m wide? Use the meaning of the word.

5

What does dehydrated mean? (de- = remove)

6

What is an astronaut? (naut = sailor)

7

Spell the word for using something again, built from re + cycl + e.

More practice: warm-up

1

What does -logy mean?

2

What does poly mean?

3

What does chron mean?

4

What does sphere mean?

5

What does peri mean?

More practice: on your own

1

What is geology? Give one thing a geologist might study.

2

A circle has a diameter of 10 cm. Use the word parts to explain what that measures.

3

Canada is in the Northern Hemisphere. Explain hemisphere using its parts.

4

Why does synchronize have a y and a ch? What does it mean? (syn = together)

5

Choose the correct spelling: perimetre or perimeter? Explain.

Challenge

1

Is a square a polygon? Is a circle? Explain using the word parts.

2

Invent a sensible word for the study of snow using a Greek part you know, and explain it. (You can use the English word snow or make one up.)

3

A garden is a rectangle 8 m long and 6 m wide. Mr. Singh wants a fence around it and a path diagonally across it from corner to corner. Which needs the perimeter? What is the perimeter? What does diagonal mean?

Check your understanding

Quiz

1.

What does hydro mean?

2.

What is the perimeter of a shape?

3.

How many sides does an octagon have?

4.

What does chronological order mean?

5.

Which word means the study of animals?

6.

Which word is spelled correctly?

For parents and teachers

Big idea (B2.1, B2.2, A3.1): Grade 5 students apply morphological knowledge to new words in context, including words from other subjects. Greek combining forms are everywhere in math (polygon, perimeter, diameter) and science (hydroelectric, hemisphere, atmosphere). Making these links is the cross-curricular connection Strand A asks for.

How to help at home:

  • During math homework, ask your child to explain what perimeter or hexagon means using the word parts.
  • Spot Greek parts on everyday items: the hydro bill, a thermometer, a recycling bin.
  • Talk about the spelling clues: when a science word has ph, ch (/k/) or a y in the middle, it's probably Greek.

Common difficulties:

  • Confusing perimeter and area. The word parts help: peri = around.
  • Spelling Greek words by sound (sycle, kronological). Remind them of the c, ch and y clues.
  • meter/metre. In Canadian spelling, the unit is metre; measuring tools and math words like perimeter use -meter.