限度 (xiàndù) is a noun meaning 'limit' as a general boundary or cap, e.g., 超过限度 'exceed the limit'. Unlike 限制 (xiànzhì), which can be a verb meaning 'to restrict' or a noun meaning 'restriction/constraint', 限度 is only a noun and focuses on the point or range that should not be exceeded. It is broader than 界限 (jièxiàn 'boundary/dividing line') and 上限 (shàngxiàn 'upper limit/cap'), which are more specific.