The Collaborative International Dictionary
monestrous
monestrous \mon*es"trous\, a. (Zool.) Having only one estrus period per breeding cycle or per year; -- of certain mammals.
Wiktionary
monestrous
a. (label en biology) Of or pertaining to a mammal, such as the dog, that only enters into heat once during each of its normal breeding cycles.
WordNet
monestrous
adj. having one estrous cycle per year [syn: monoestrous]