Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
synchromesh is a noun meaning "an automotive system for shifting gears in which the gears revolve at the same speed and so shift smoothly". It carries one recorded sense.
an automotive system for shifting gears in which the gears revolve at the same speed and so shift smoothly
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for synchromesh come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.