Glossary
afebrile
Afebrile means without fever, and the word is built from the negation prefix a- plus febrile, meaning feverish.
Afebrile means the patient has no fever: a- is a negation prefix and febrile means feverish, so the whole word is fever turned off. It is a good example of why the front of a long word is worth reading first, because a reader who sees only febrile takes the opposite meaning from the note. The pair to learn is febrile and afebrile, and the related antipyretic, a drug that lowers fever. In a passage, the word is usually doing real work in an argument — a patient described as afebrile is being contrasted with one whose temperature is up, and a question about the difference is testing the negation, not the vocabulary.
Taught in
Related terms
- word part — A word part is a prefix, root, suffix or combining vowel — one of the pieces a medical word is built from.
- 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)