outer space is a noun meaning "any location outside the Earth's atmosphere". It carries one recorded sense.
any location outside the Earth's atmosphere
“the astronauts walked in outer space without a tether”
“the first major milestone in space exploration was in 1957, when the USSR's Sputnik 1 orbited the Earth”
Definitions, synonyms and semantic relations for outer space come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.