noun
or oes·trus ˈestrəs, chiefly Brit ˈēs- ; also es·trum or oes·trum -rəm
( plural estruses or oestruses also estrums or oestrums )
Usage: often attributive
Etymology: New Latin, from Latin oestrus gadfly, frenzy, from Greek oistros — more at ire
1.
a. : a regularly recurrent state of sexual excitability during which the female of most mammals will accept the male and is capable of conceiving : heat
b. : a single occurrence of this state
the next estrus was delayed
2. : estrous cycle