异态 (yìtài) is a formal noun meaning 'abnormal state' or 'atypical condition', often used in scientific, medical, or veterinary contexts. The character 异 (yì) means 'different', 'unusual', or 'abnormal', while 态 (tài) means 'state', 'condition', or 'manner'. Together, they denote a deviation from the normal physiological or behavioral pattern—especially in living organisms. This term is rarely used in casual speech and appears most frequently in technical reports, clinical notes, or academic discussions about health anomalies.

In animal-related usage, 异态 commonly describes observable physical or behavioral abnormalities—such as unusual posture, irregular gait, abnormal coat texture, or atypical social interaction in livestock or pets. It implies an objective, measurable deviation rather than subjective discomfort or illness per se. While it can overlap with terms like 'symptom' or 'sign', 异态 emphasizes the descriptive, categorical nature of the deviation itself—not its cause or severity.