anestrus

from WordNet (r) 3.0 (2006)

anestrus
    n 1: applies to nonhuman mammals: a state or interval of sexual
         inactivity between two periods of estrus [syn: {anestrus},
         {anestrum}, {anoestrus}, {anoestrum}] [ant: {estrus},
         {heat}, {oestrus}, {rut}]

from The Collaborative International Dictionary of English v.0.48

anestrus \anestrus\ n.
   A state or interval of sexual inactivity between two periods
   of estrus; -- applies to nonhuman mammals. [Also spelled
   {anoestrus}.]
   [WordNet 1.5]

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