diœstrusn.

1900 W. Heape in Q. Jrnl. Microsc. Sci. 44 8 Diœstrum, or the Diœstrous Period.—This is a brief period lasting only a few days... It is followed at once by a new pro-œstrum, and the four periods, pro-œstrum, œstrus, metœstrum, and diœstrum, I have designated the diœstrous cycle.

1923 Physiol. Rev. 3 458 The interval of quietude following oestrus is called ‘dioestrus’ if it be only a relatively brief interlude between regularly recurrent oestrous periods, ‘anoestrus’ if it be so long as to cover a large part of the year between mating seasons.

1937 Nature 4 Dec. 949/2 The diœstrus is not simply a quiescent period, but is now known to be of the nature of an abbreviated pseudo-pregnancy.

1957 Encycl. Brit. XIX. 173/2 If coition does not take place at the first oestrus, or if for some other reason the ova discharged at ovulation are not fertilized, the animal, instead of experiencing a prolonged pseudopregnancy followed by an anoestrum (as with the bitch), undergoes a short period of apparent quiescence, called by Heape the dioestrum, then comes to heat again.

1966 McGraw-Hill Encycl. Sci. & Technol. (rev. ed.) XI. 476/1 After metestrus a relatively longer period of diestrus occurs before proestrus recurs... All these phases can be demonstrated in the guinea pig and rat.

1973 Nature 12 Jan. 129/2 When the drug was administered on other days of the cycle, metoestrus, dioestrus or pro-oestrus, it failed to increase ovulation rate.

1956 Nature 4 Feb. 235/1 These groups were of pro-œstrous, œstrous, metœstrous and diœstrous rats.

1974 D. Webster & M. Webster Compar. Vertebr. Morphol. xviii. 476 This is the diestrous period. It brings the estrous cycle fully around to where it can either be extended in a long asexual period..or..yield to a new proestrous period immediately.