If 子 used at the end of a noun, then it's a noun Suffix 子 zi The character 子 zi literally means offspring or child, but it is also used as a noun suffix. You can often find it in a lot of nouns, like 兔子 (tùzi, rabbit), 帽子(màozi, hat), and 盒子 (hézi, box), which end with this neutral toned “zi 子”. About this grammar point, why we need this 子zi as a noun ending? Each character in Chinese is a unit of meaning and a character can be used in a variety of different words as well. However, Chinese is not a monosyllabic language. Most words in modern Chinese are actually multisyllabic, which are made up of more than one character, usually two, but there can be three or more. So, most English words could be translated into a Chinese bigram of two Chinese characters. Hence, that's why we put 子 zi ending after one-syllable nouns in Chinese, even though it does not have any significant meanings in these nouns. You can regard it as "stuff". Let take a look at these examples again: 兔(tù,rabbit) --> 兔子 (tùzi, rabbit) 帽(mào, hat) --> 帽子(màozi, hat) 盒 (hé, box) --> 盒子 (hézi, box) We put zi 子 after the monosyllabic nouns. However, we do not put zi 子 after a noun which is a bigram . For example, 白兔 (bái tù) = white rabbit (Note that the noun-making suffix “zi” drops off.) 红帽 (hóng mào) = red hat 木盒 (mù hé) = wooden box I hope it helps.

Some common usage... 1. describes something diminutive, e.g. 石子 (stone, pebble vs rock) 2. a term used for people. Think of it as "a person" e.g. 妻子 (person wife, as opposed to the "wife of animals, spirits etc", 舟子 (boatman/boat person), 才子 (a talented person) 3. an honorific e.g. 孔子, 老子, 莊子. This can be translated as "master", Master Kung etc.