adj

• (music) Evoking or creating an atmosphere: atmospheric.
• (mathematics) Containing objects or describing a setting that one is interested in.
  "These, then, are characterizations of the system of natural numbers within an ambient set theory. And they seem to work, in the sense that in a sufficiently strong set theory it can be shown that Peano's axioms have (up to isomorphism) a unique model (cf. Rem. 6.1.8)."

noun

• (astrology) The atmosphere; the surrounding air or sky; atmospheric components collectively such as air, clouds, water vapour, hail, etc.
  "It might be also, that attracted by that great void Vacuum ... all the ambients would be rarified, and particularly, the air."
• (uncountable, music) A type of modern music that creates a relaxing and peaceful atmosphere.
  "Ambient can be flabby synth mulch that needs to access cyberism and external philosophies to convince you you're not being scammed."