oestrus

O1E1S1T1R1U1S1
/ˈiːstɹəs//ˈɛstɹəs/

noun

A biting fly of the genus Oestrus; a botfly.

UncommonScrabble 7

Meanings

nounoestrus (countable and uncountable, plural oestruses or oestri)

plural oestruses · plural oestri · alternative archaic œstrus · alternative US estrus

  1. countableA biting fly of the genus Oestrus; a botfly.

    […] and which is produced by the larvae of oestri and particularly of Oestrus hemorrhoidalis.

    1915, American Veterinary Review, page 407
    1 more example

    If this is inseparable from the oeconomy of nature, it necessarily follows that man must be subject to the depredations of oestri, ichneumons, . . . and perhaps, thousands of others, which the senses, aided by the directions of a correct understanding, may be able to trace in a way that will fall very little short of absolute demonstration.

    1963, Bacteriological Reviews, page 92, column 1
  2. countableA bite or sting.
  3. archaiccountableA passion or frenzy.
  4. countableuncountablebiologyA female animal's readiness to mate.

    Intervals between oestri and between ovulations in dairy cows within 100 days post partum

    1980, The Zimbabwe Journal of Agricultural Research, page 73
    5 more examples

    In those monoestrous species in which the male is capable all the year round, it is found that the oestri of individual females come at different seasons.

    1910, Cleveland Medical Journal, page 517

    A vasectomized Philippine carabao bull was used as a teaser to determine the occurrence and recurrence of oestri.

    1939, The Philippine Agriculturist, page 289

    An evaluation was carried out so that the mean number of oestri per one animal was calculated for 14 days in the three periods: […]

    1962, Neoplasma, page 152

    It’s the supremely human act, freely to fuck, not because you are on heat, or in oestrus, like an animal, but to give and receive pleasure.

    2001, David Lodge, Thinks...

    The substantial genital swelling of [female chimpanzees] during oestrus may facilitate transmission of viruses by making the mucosa more fragile.

    2011, Jacques Pepin, “The Source”, in The Origins of AIDS, 1st edition, →ISBN, page 29

Synonyms & antonyms

nounapplies to nonhuman mammals: a state or period of heightened sexual arousal and activity

Broader
physical conditionphysiological statephysiological condition

Synonym sets from Open English WordNet, CC BY 4.0.

Origin

  1. Proto-Indo-European*h₁eysh₂-
  2. Ancient Greekοἶστρος (oîstros)
  3. Latinoestrus
  4. Englishoestrus

Borrowed from Latin oestrus (“gadfly, sting, frenzy”), from Ancient Greek οἶστρος (oîstros), from Proto-Indo-European *h₁eys-, used to form words denoting passion; see also Latin īra (“anger”), Lithuanian aistra (“violent passion”), Avestan 𐬀𐬈𐬯𐬨𐬀 (aesma, “anger”).

Full word history & related roots →

Translations

Bulgarian разгонване
  • разгонване (razgonvane)a female animal's readiness to mate
Chinese Mandarin 發情 /发情
  • 發情 /发情 (fāqíng)a female animal's readiness to mate
Czech říje
  • říjea female animal's readiness to mate
Esperanto oestro
  • oestroa female animal's readiness to mate
Finnish kiima
  • kiimaa female animal's readiness to mate
French œstrus, chaleur
  • œstrusa female animal's readiness to mate
  • chaleura female animal's readiness to mate
German Brunst, Hitze
  • Brunsta female animal's readiness to mate
  • Hitzea female animal's readiness to mate
Greek οίστρος
  • οίστρος (oístros)a female animal's readiness to mate
Hebrew יִחוּם
  • יִחוּם (yichúm)a female animal's readiness to mate
Hungarian tüzelés, ivarzás
  • tüzelésa female animal's readiness to mate
  • ivarzása female animal's readiness to mate
Irish éastras
  • éastrasa female animal's readiness to mate
Italian estro, calore
  • estroa female animal's readiness to mate
  • calorea female animal's readiness to mate
Japanese 発情
  • 発情 (hatsujō)a female animal's readiness to mate
Korean 발정
  • 발정 (baljeong)a female animal's readiness to mate
Malay estrus
  • estrusa female animal's readiness to mate
Polish ruja
  • rujaa female animal's readiness to mate
Portuguese estro, cio
  • estroa female animal's readiness to mate
  • cioa female animal's readiness to mate
Russian те́чка, э́струс
  • те́чка (téčka)a female animal's readiness to mate
  • э́струс (éstrus)a female animal's readiness to mate
Spanish estro, celo
  • estroa female animal's readiness to mate
  • celoa female animal's readiness to mate
  • bramaa female animal's readiness to mate
  • berreaa female animal's readiness to mate
  • cachondeza female animal's readiness to mate

Rhymes & wordplay

Anagrams

Cite this entry
APA

oestrus. (n.d.). In WatkinsX Dictionary. Retrieved November 2, 2026, from https://dictionary.watkinsx.com/word/oestrus

MLA

“oestrus.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/oestrus. Accessed November 2, 2026.

Chicago

WatkinsX Dictionary, s.v. “oestrus,” accessed November 2, 2026, https://dictionary.watkinsx.com/word/oestrus.

Source: oestrus on Wiktionary, CC BY-SA 4.0.