Ma'anar ƙamus na kalmar "reactivity" ita ce dabi'ar wani abu ko abu don fuskantar wani abu na sinadarai, ko nuna amsa ko amsa ga wani abin ƙarfafawa ko canji a cikin muhalli. Ma'ana, reactivity yana nufin ikon wani abu ko tsarin da zai iya amsawa ko amsa wani abu a kewayensa. Ana amfani da kalmar sau da yawa a cikin ilmin sunadarai, kimiyyar lissafi, da ilmin halitta don bayyana halayen abubuwa daban-daban, sunadarai, da kwayoyin halitta.