What does "traversed" mean here?

I looked "beat" up in Merriam-Webster dictionary. https://www.merriam-webster.com/dictionary/beat

Entry 2 Sense 7 b: one of the reaches (see REACH entry 2 sense 1) in the zigzag course so traversed : TACK

What does the "so traversed" mean here? Is traversed an adjective? But the dictionary shows "traversed" is the past tense of traverse, not an adjective.