WORD	GRADE TESTED*	% KNOWN*	MEANING KNOWN*	SUGGESTED CONTEXT
aboriginal	16	89%	native	biology, Australia
anaerobic	12	59%	growing without oxygen	biology
antidote	10	71	against poison	biology, epidemiology (plants, snakes, diseases)
aphelion	16	56%	point farthest from the sun	astronomy
apogee	13	69%	point farthest from the earth	astronomy
buttress	10, 12	72%, 73%	to prop up, strengthen; support	biology - try tree contexts
cacophony	16	44		zoology (birds?), physics (acoustics, music)
capacity	08; 10	77%	ability; position served in	any science or math context
detritus	16	19%	debris	biology, zoology, ecology (fish, sometimes found with estuary/estuaries)
distal	13	34%; 39%	far away from center; far away from origin	biology, zoology, anatomy, marine biology
efficacy	16	61%	power to produce effect	medicine
estuary	13	32%	sea drowned river mouth	marine biology - fish, ecology
fissure	13	59%	deep crack	geology (rocks, earthquakes)
innocuous	16	46%	harmless	almost any SMET text
juncture	13	92%	critical moment	almost any SMET text
kelp	13;	76%	seaweed	biology, oceanography

WORD	GRADE TESTED*	% KNOWN*	MEANING KNOWN*	SUGGESTED CONTEXT
labyrinth	12	58%; 61%	hard to find way through; puzzling path	medicine, scientific research
metamorphosis	10	72%	change of form	biology (caterpillars, moths, butterflies)
myriad	12	53%	great number of	almost any science
negligible	13	66%	unimportant
obsolete	10	71%	out of date	any SMET context
paucity	16	45%; 43%	scantiness; scarcity	any SMET context
pendulous	12	71%	loose-hanging	biology
query	12	67%, 70%	to question; question	any SMET context
resilient; resilience	12	55%; 55%	springing back; elasticity	biology
silt	12	70%	biology, ecology, rivers, creeks	biology
simian	16	53%	apelike	epidemiology (origin of AIDS), biology
transient; transience	13; 12	71%; 37%	not staying long; passing on quickly	biology
ubiquitous	16	34%	present everywhere
variable	08	83%	changeable
writhe	12	75%	twist about	snakes
embellish	16	78%	add ornament to
obscure	12	83%	to conceal
equinox	13	86%	equal day and night	astronomy

Word meanings derived from:

*Dale, E. & O'Rourke, J.O. (1976). The living word vocabulary: The words we know - a national vocabulary inventory. Elgin, IL: Field Enterprises Educational Corporation.

Dale and O'Rourke measured word meaning knowledge through multiple choice word meaning tests. They tested target words at various grade levels: grades 4, 6, 8, 10, 12, 13, and 16. During the trials, if a word received a score of 66% or higher, that word was retested at the next level. According to Dale and O'Rourke, a final score between 67-84% is desirable if a word is to be used in a text to be read independently by that level of student. Scores less than 50% mean that the word is a hard word. Scores less than 33% mean that the majority of students at that grade has no knowledge of the word.

The words chosen are arbitrary; they were selected randomly by scanning available words with upper school students in mind. A science context was assumed for most words.