Synonyms for Laughing gas:

n.

carbon, chlorofluorocarbon, cfc. artifact (noun)
nitrous oxide.
gas (noun)
atmosphere, acetylene, fume, carbon monoxide, hydrogen, nitrogen, natural gas, ammonia, oxygen, helium, carbon dioxide, miasma, vapor, neon, nerve gas, ethane, rarefaction, butane, argon, chlorine, xenon, gas, ozone, methane, tear gas, ether.
laughing gas (noun)
nitrous oxide.

Other synonyms:

Other relevant words:
nitrous oxide.