Kalmar "homoiothermic" sifa ce da ke bayyana ikon kwayoyin halitta don kiyaye yanayin zafin jiki na ɗan lokaci ba tare da la'akari da canje-canje a yanayin waje ba. Ana amfani da kalmar sau da yawa dangane da dabbobi masu ɗumi-ɗumi kamar dabbobi masu shayarwa da tsuntsaye, waɗanda za su iya daidaita yanayin cikin su ta hanyar tsarin rayuwa da daidaita yanayin jiki kamar rawar jiki ko gumi.A taƙaice, "homoiothermic" yana nufin. yana da yawan zafin jiki na cikin gida, sau da yawa yana nufin dabbobi masu jinni.