the GNU version of the Collaborative International Dictionary of English
n. The febrile condition.
The Century Dictionary and Cyclopedia
n. A higher bodily temperature than is normal; fever.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. a rise in the temperature of the body; frequently a symptom of infection
Word Usage
"If, however, organic disease can be excluded, and if the pyrexia is the only circumstance which prevents the decision that the child is well and should be treated as well, then the thermometer may be overruled and the pyrexia neglected."