the.com/availability

means The quality of being free, reachable, or on-hand when someone or something needs you.

from From French disponibilité-style formations via 'available,' which traces to Latin ad- ('to') plus valere ('to be strong, to be worth') — the same root that gives us 'valid' and 'value.' To be available was literally to have enough strength or worth left to be useful for a task. The word drifted from 'having the capacity to serve a purpose' to 'being present and accessible at a given moment' — a quiet shift from an inner quality to an outward state, which is exactly how it ended up measuring your worth by your response time.