A characteristic of a vehicle that describes the likelihood of it and/or its
occupants surviving on an active
battlefield. How this is determined will differ depending on the vehicle's type, configuration and mission, so the term is typically only used in a specific quantitative sense in a specific context, with definition provided for that context.
For example, the survivability for a main battle tank would involve such factors as its ability not only to withstand hits from enemy weapons, but which weapons would be employed against it, what engagement ranges those weapons were expected to be employed at, the visibility of the tank in the conditions it was expected to be used in especially in terms of the sighting or seeking ability of those weapons, etc.
On the other hand, a submarine's survivability might depend much more heavily on its ability to avoid detection, outrun pursuit, and lose pursuers if they tried to engage it - and much less heavily on the boat's ability to survive hits or to evade weapons actually launched against it.
In a particular analysis, if the term survivability is used, the analyst should be expected to provide not only a definition of survivability but a quantitative representation for his or her analysis, along with an explanation or reference for that representation.