2. A potentially fatal viral disease of animals. especially dogs and cats, characterized by rhinitis (inflammation of the mucous membrane lining the nose ), fever, and a loss of appetite: Distemper is a virus which can be extremely contagious among the canine animals and causes coughing and fever.
3. Etymology: from Old French destemprer,"to put out of order"; from Middle Latin distemperare from dis-, "undoing, reversal" + Latin temperare, "to mingle in due proportion, to combine properly, to moderate, to regulate"; from tempus, temporis, "time".
English has two distinct words for distemper although ultimately they come from the same source.
Latin temperare, "mingle" (source of English temper; derived from Latin tempus, "time, due time"; from temperate, and temperature. This formed the basis of two separate medieval Latin verbs, both compounded from the prefix dis- but using it in quite different ways.
- Dis- in the sense "reversal of a current state" joined with temperare in the specialized meaning, "mingle in proper proportion" to produce distemperare, "to upset the proper balance of bodily humours"; hence, "to vex, to make ill".
This passed directly into English as distemper, and survives today mainly as the term for an infectious disease of dogs and cats.
- Dis- joined with temperare in its intensive function produced medieval Latin distemperare, "to mix thoroughly, to soak", which entered English via Old French destemprer in the 14th century.
The meaning "to soak, to steep, to infuse" survived until the 17th century. The word's modern application, to a water-based decorator's paint, comes from the fact that the pigment is mixed with or infused in water (the same notion lies behind tempera, borrowed from Italian).