MANY LARGE words that are used every day are made up of small, pieces of words called roots or combining forms. The roots come from other languages like Greek and Latin and, when combined, form common English words. For instance, using the four roots:
tele-, from Greek meaning far
micro-, from Greek meaning small
scope, from Greek meaning to look, watch or see
phone, from Greek meaning sound
several common words can be made such as:
telephone, allows far-away sound to be heard
telescope, allows far away objects to be seen
microphone, allows small sounds to be heard
microscope, allows small objects to be seen
The names of dinosaurs are formed the same way. Although they often seem to be merely long strings of random letters designed by scientists specifically to be difficult to pronounce, the names of the animals are combinations of word roots that always describe something about the animal. For example, combining the following three roots:
tri-, from Latin meaning three
cerat-, from Greek meaning horn
-ops, from Greek meaning face gives the name for
Triceratops, a dinosaur with a three-horned face.

Another difficult sounding dinosaur name is Pachycephalosaurus. Broken down into its combining forms it means:

pachy-, from Greek meaning thick
cephalo-, from Greek meaning head
-saurus, from the Greek meaning lizard
This is not a comment on the animal's intelligence. It is a description of an animal with a projection on the upper part of the skull making the head look thicker than normal.
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Dinosaur names can also describe where the animal was first discovered:

Albertosaurus was discovered in the province of Alberta, Canada
Bactrosaurus was discovered in Bactria, Mongolia
Other dinosaur names honor the person who was instrumental in the discovery:
Lambeosaurus was named for Lawrence Lambe, a paleontologist with the Geological Survey of Canada.
Diplodocus carnegii was named for Andrew Carnegie who financed the expedition for its discovery.


The combining forms which produce dinosaur names come from the languages of Greek and Latin. Not coincidentally many of those same forms are found in everyday words in English: corrugated cardboard (L, corrugat-), dinner plate (G, platy-). In the following activity, students will appreciate how descriptive dinosaur names are formed. In this activity students will use multiple combining forms added to the suffix "-saurus" (Greek for lizard) to form the name of a "dinosaur" which they will then draw.

Time: approximately 60 minutes


— six containers (plastic bucket or envelope; something opaque)
— six small cards of six different colors; total 36 (business-card size or similar)
— drawing paper for each student
— colored pencils, crayons or markers for each student

Grouping: Divide the class into six groups


1) Before class write each of the 36 combining forms from Table 1 on a separate card, listing the combining forms and the meaning. Put each group into a separate container, centrally located in the room so it is readily accessible to all students. Having six colors will avoid cards being mixed up. Cards could be laminated to avoid repetition of this time-consuming step.

2) Divide the class into six groups and arrange the six groups so they form a circle around the six centrally located containers.

3) Explain that each bucket contains a word that may be used to describe an animal. Ask one member of each group to select one card from each container as a sample and read them to the students. For example, one combination might be, "albi-, grandi-, plani-, lasio-, duo-, ungui-." These would be combined with the word -saurus, to form: "albigrandiplanilasioduounguisaurus," or, in English, a "white, large, flat, hairy, two-clawed lizard". Students should be encouraged to rearrange the six descriptors any way they would like.
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4) After selecting the dinosaur descriptors, a member of the group should read the six selected cards aloud to the class.

5) Distribute drawing materials to each student.

6) Each member of the group should then draw a picture of the animal described by the six combining forms and write the combining forms across the bottom of the drawing.

7.At the end of the allotted time have each group present all of their drawings to the class.

Table 1. (G) indicates a combining form from Greek and (L) indicates a combining form from Latin.

black - (L) atri-, nigri-; (G) melano-.
blue - (L) cerule-; (G) cyano-.
green - (L) viridi-; (G) chloro-.
white - (L) albi-; (G) leuco-.
yellow - (L) flav-; (G) xantho-.
dwarf - (L) pumili-; (G) nano-
gigantic - (L) ingenti-; (G) colosso-.
large - (L) grandi-; (G) macro-, mega-.
short - (L) brevi-; (G) brachy-
tall - (L) proceri-, alti-; (G) aepy-.
curved - (G) cyrto-, gampso-.
egg-shaped - (L) ovat-
flat - (L) plani-; (G) platy-.
hollow - (L) cavi-; (G) coelo-.
horned - (L) cornut-; (G) cerato-.
round - (L) circuli-; (G) cyclo-, gyro-.
bare - (L) nudi-; (G) gymno-.
bearded - (L) criniti-; (G) pogono-.
hairy - (L) hirsut-; (G) lasio-, trichodo-
rough - (L) asper-; (G) trachy-.
spiny - (L) spini-; (G) acantho-, echino-.
wrinkled - (L) corrugat-; (G) rugos-.
one - (L) mono-; (G) uni-.
two - (L) bi-, duo; (G) di-.
three - (L) tri-; (G) tria-.
four - (L) quadri-; (G) tetra-.
seven - (L) septem-; (G) hepta-.
ten - (L) decim-; (G) deca-
Animal Parts
beak - (L) rostr-; (G) rhyncho-.
claw - (L) ungui-; (G) chelo-, onycho-.
foot - (L) pedi-; (G) podo-.
head - (L) capit-; (G) cephalo-.
tail - (L) caud-; (G) cerco-.
tooth - (L) denti-; (G) odonto-.


1) The drawing can be combined with a writing activity where students must write a paragraph describing their animal instead of, or in addition to, step 7.
2) Two students can be asked to write a longer story explaining what would happen if their two dinosaurs met one another.
3) Students can be encouraged (extra credit, competition among student groups, peanuts) to look through the dictionary for words that may contain the combining forms they selected for their dinosaur.
4) Table 2 is a list of combining forms taken only from dinosaur names. As dinosaurs are studied in class, students could use this as a reference checklist to see what the names mean. It could be enlarged as new roots are found and kept as a reference wall chart. As new discoveries are announced in the media, they can also be added making it state-of-the-art.
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Borror, Donald J., 1960, Dictionary of Word Roots and Combining Forms. Palo Alto, California: Mayfield, 1960.

Munsart, Craig A., Investigating Science With Dinosaurs. Englewood, Colorado: Teacher Ideas Press, 1994.

Norman, David. The Illustrated Encyclopedia of Dinosaurs. New York: Crown, 1985.

Table 2. Greek and Latin Descriptors
a, ar, and no, not
acro top
allo strange
alti tall, high
angusti sharp
apato deceptive
baro heavy, pressure
bi two
brachio arm
brachy short
bronto thunder
canthus spiked, spined
cera horned
coelo hollow
compso pretty
datyl finger
deino terrible
derm skin
di two
don, den tooth
dromaeo running
drypto wounding
echino elasmo
elmi foot
gnathus jaw
hetero mixed
lana wooly
lepto slender
lestes robber
lopho ridged
luro tail
macro large
maia good mother
mega huge
metro measured
mimus mimic
mono single
morpho shaped
mucro pointed
nano dwarf
nodo lumpy
nycho clawed
ornitho bird
pachy thick
ped, pos, pes foot
penta five
phalangia toes
phobo fearsome
placo, plateo flat
pola, poly many
preno sloping
ptero winged
quadri four
raptor thief
rex king
rhinot nose
saurus lizard, reptile
segno slow
stego roofed
steneo narrow
stenotes finger
stereo twin
stuthio ostrich
tarbo alarming
tetra four
thero beast
top head, face
tri three
tyranno tyrant
velox, veloci speedy, fast

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