extending in the same direction and always the same distance apart
of lines or surfaces: extending in the same direction and at all points the same distance apart
in computing, performing several operations simultaneously
denoting an electrical circuit having a number of conductors in parallel
analogous or comparable
said of phrases, sentences, etc: having identical types of word in corresponding positions
said of two or more melodies or musical parts: keeping the same distance apart in musical pitch
parallelism noun
[via Latin from Greek parallēlos beside another, from para-1 + allēlōs one another]