1) Engine technology 
A piece sewn around the hood of a sleeping bag to keep in warm air.
A head gasket is a gasket that sits between the engine block and cylinder head(s) in an internal combustion engine. Its purpose is to seal the cylinders to ensure maximum compression and avoid leakage of coolant or engine oil into the cylinders; as such, it is the most critical sealing application in any engine, and, as part of the combustion cham...
[n] - a gasket to seal a cylinder head
noun a gasket to seal a cylinder head