Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
one-to-one is an adjective meaning "used of relations such that each member of one set is associated with one member of a second set". It carries one recorded sense.
used of relations such that each member of one set is associated with one member of a second set
Definitions, synonyms and semantic relations for one-to-one come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.