eq·ua·bil·i·ty \ˌekwəˈbiləd.ē, -lətē, -i also ˌēk-\noun (-es) Etymology: Latin aequabilitas, from aequabilis + -itas -ity 1.: the quality or condition of being equable < equability of temperature > : equanimity < they lacked our gusto as surely as we lacked their equability — John Mason Brown > 2.archaic: comparability as equals or on equal terms