We don't have synonyms for airstone yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are hailstone, air stone and hairstone.
(n) :
A piece of aquarium furniture, traditionally limewood or porous stone, whose purpose is to diffuse oxygen gradually into the tank, eliminating the noise and large bubbles of conventional air filtration systems.
(n) :
A piece of aquarium furniture, traditionally limewood or porous stone, whose purpose is to diffuse oxygen gradually into the tank, eliminating the noise and large bubbles of conventional air filtration systems.