A round gourd that floats, for example, is called a p'ao, while one with an equally thick top and bottom is called a hu.
李時珍並且仔細地作了一番解釋：圓形的壺蘆原本叫匏，也稱瓢，因為可浮水，性如泡、漂，再由於蓏屬植物皆可稱瓜，故又可稱瓢瓜、匏瓜；事實上，匏、瓢、壺、瓠，是一件東西，可以通稱。