Crenulate

crenulate \ˈkren-yə-lət, -ˌlāt\ or crenulated \ˈkren-yə-ˌlā-təd\ adjective: having an irregularly wavy or serrate outline {a crenulated shoreline}

Etymology: New Latin crenulatus, from crenula, diminutive of Medieval Latin crena notch

Everyone uses the past participle of the verb serrate as an adjective (as in “a serrated knife”), but did you know that serrate by itself can be an adjective? In that case the stress may be placed on the first syllable.