isul noun English. A small plant whose leaves are sometimes chewed with betelnut. Example sentence: Subanen. Ki gisul, ginis sigbet, pegbulak di tapay. Ki tapay ndi' mbaluy sa' nda'iduni gisul dun. English. Isul is a kind of wild plant, a garnish for wine starter. Wine starter can't be made without some isul. Generic. mula