Crossword clues for the word: MAINSTEM The word MAINSTEM has appeared as an answer to at least 5 crossword clues on different crossword puzzles. Crossword clues for MAINSTEM Showing 1 to 5 of 5 results Clue(s) "Broadway or State St., e.g." "Broadway, for one." Broadway: Colloq. River's principal channel Town's principal road