All Chinese characters are logograms, but several different types can be identified, based on the manner in which they are formed or derived. There are a handful which derive from pictographs (象形 pinyin: xiàngxíng) and a number which are ideographic (指事 zhǐshì) in origin, including compound ideographs (會意 huìyì), but the vast majority originated as phono-semantic compounds (形聲 xíngshēng). The other categories in the traditional system of classification are rebus or phonetic loan characters (假借 jiǎjiè) and "derivative cognates" (轉注 zhuǎn zhù). Modern scholars have proposed various revised systems, rejecting some of the traditional categories.