Adjective : parallel rows of trees. ,Canada and the U.S. have many parallel economic interests. ,a parallel circuit. ,Some computer systems join more than one CPU for parallel processing.    From Dictionary.com. 

Noun : a case history without a known parallel. ,These two cases have some parallel with each other.    From Dictionary.com. 

Verb (used with object) : The road parallels the river.    From Dictionary.com.