Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
long-run is an adjective meaning "relating to or extending over a relatively long time". It carries one recorded sense.
relating to or extending over a relatively long time
“the long-run significance of the elections”
“the long-term reconstruction of countries damaged by the war”
“a long-term investment”
Definitions, synonyms and semantic relations for long-run come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.