Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
allochthonous is an adjective meaning "of rocks, deposits, etc.; found in a place other than where they and their constituents were formed". It carries one recorded sense.
of rocks, deposits, etc.; found in a place other than where they and their constituents were formed
Definitions, synonyms and semantic relations for allochthonous come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.