one million million million is a noun meaning "the number that is represented as a one followed by 18 zeros". It carries one recorded sense.
the number that is represented as a one followed by 18 zeros
“in England they call a quintillion a trillion”
United Kingdom · Germany
Definitions, synonyms and semantic relations for one million million million come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.