The word tenable comes from the Latin tenere, meaning "to hold" or "to keep." It is used to describe something that is defensible, sustainable, or capable of being maintained or supported. In various contexts, tenable refers to an argument, position, or situation that can be justified or defended against criticism or attack. It suggests that something is reasonable, valid, or credible under scrutiny, whether it is an opinion, a belief, or even a physical structure.

In academic, logical, or philosophical discussions, tenable refers to ideas or theories that are capable of being supported by evidence or reasoning. For example, a tenable hypothesis is one that holds up against testing or criticism. Outside of intellectual contexts, tenable can also refer to a position, job, or place that is capable of being maintained or continued, without being vulnerable to immediate challenge.