Gasket n. : A line or band used to lash a furled sail securely. Sea gaskets are common lines; harbor gaskets are plaited and decorated lines or bands. Called also casket.

Gasket n. : The plaited hemp used for packing a piston, as of the steam engine and its pumps.

Gasket n. : Any ring or washer of packing.

Example:
How much is a new head Gasket with installation on a 95 Mustang?

Taxonomy
gasket, metal, stress, flange, compression, Sheet gaskets, gasket materials, elements, paper gaskets, Spiral-wound gaskets, application, filler material, metal core, surfaces, seating surface, free encyclopedia, improvement, compression ring.

Defination from the web:
gasket is a mechanical seal that fills the space between two mating surfaces, generally to prevent leakage from or into the joined objects while under compression. ... It is usually desirable that the gasket be made from a material that is to some degree yielding such that it is ...