clathrate hydrate
Technical term in chemistry for a crystalline water-based solid physically resembling ice, in which small non-polar molecules are trapped inside 'cages' of hydrogen-bonded water molecules.
Methane hydrate is a type of clathrate hydrate.
A specific clathrate hydrate containing methane; 包接水和物 is the broader category.
Compound of 包接 (inclusion) + 水和物 (hydrate). The exact derivation is uncertain; the term is a modern technical coinage.