Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
rectilineal is an adjective meaning "characterized by a straight line or lines". It carries one recorded sense.
characterized by a straight line or lines
“rectilinear patterns in wallpaper”
“the rectilinear propagation of light”
Definitions, synonyms and semantic relations for rectilineal come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.