A rise in the temperature of the body; frequently a symptom of infection. A fever occurs when your temperature rises above its normal range. What’s normal for you may be a little higher or lower than the average temperature of 98.6 F.
That’s why it’s hard to say just what a fever is. But a “significant” fever is usually defined as an oral or ear temperature of 102 F or a rectal temperature of 103 F. If you’re an adult, a fever may be uncomfortable, but it usually isn’t dangerous unless it rises above 103 F. For very young children and infants, however, even slightly elevated temperatures may indicate a serious infection