Skeleton
Skeleton (noun) /ˈskel.ɪ.tən/ US /-ţən/
1. the structure of all the bones in humans or other vertebrate animals – bones frame:
We found several decayed human skeletons in our recent archaeological excavation.
2. the most fundamental and basic parts or ingredients of something – building block – outline – basic framework:
My supervisor supported the skeleton of my proposal. He just asked for some modifications, though.