on the other hand is an adverb meaning "(contrastive) from another point of view". It carries one recorded sense.
(contrastive) from another point of view
“on the other hand, she is too ambitious for her own good”
“then again, she might not go”
Definitions, synonyms and semantic relations for on the other hand come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.