you should understand if it is a nour or adjective. as adj.- survival mask - a thing that helps you to survive. as noun- her survival was unexpected. she is a lucky survivor. or terminal and terminator... terminal as adj. means end of something and as noun it means the end itself. so terminator then means a thing that terminates (ends) something. ex: she has a terminal sickness. (in this sentence we're sure her sickness will cause death. sickness is her terminator.

survival: the state of continuing to live or exist, often despite difficulty or danger survivor: a person who continues to live, especially despite being nearly killed or experiencing great danger or difficulty survival refers to the state of continuing to live, while survivor refers to the person who continues to to live