Glossary
confusable word
Confusable words are pairs that look or sound alike but differ in meaning and grammar, such as affect and effect, or accept and except.
A confusable word is one of a pair that look or sound close enough to be swapped, where the swap changes the meaning. Affect is usually the verb and effect the noun; accept is to receive and except to exclude; advise is the verb and advice the noun; principal is the head or the main one and principle a rule. Notice that several pairs divide along word class — the -ce form is the noun, the -se form the verb — which is the fastest way to choose between them. Others divide on meaning rather than grammar: infer is what a reader does, imply what a writer does. The exam does not test spelling as such; it tests whether the sentence needs the noun or the verb, so read the slot the word occupies and let the grammar pick the word.
Taught in
Related terms
- context clue — A context clue is information in the sentence around an unknown word that narrows what the word means — a definition, a restatement, a contrast, an example, a consequence or the general sense.
Source: MedlinePlus (US National Library of Medicine) consumer guidance on understanding medical words, which the vocabulary guide follows for the prefix, root, suffix and combining-vowel system. US federal government material, not subject to copyright in the United States. Every definition and example above was written for this course in our own words; no dictionary or glossary text is reproduced. (MedlinePlus accessed 2026-10-27; definitions written 2026-10-27)