In Mandarin Chinese, 子 (Pinyin: zǐ 🔊) has many meanings. As a noun, it can signify “a child”, “an offspring”, “a son”, “a person”, “a seed” or “an egg”, while as an adjective, it means “young” or “small”.
子 is also the first of twelve earthly branches. It corresponds to the Year of the Rat (鼠) of the Chinese zodiac; the eleventh month; the hour of the Rat (11 pm to 1 am, “the time when Rats are most active in seeking food”); and the direction 0° (i.e. north). Its associated “fixed element” is Water, 水.
Curiously, a combination of 男 “man” with 子, 男子 (nánzǐ), still means “a man”, not “a boy” as one would expect; similarly, 女 + 子 = 女子 (nǚzǐ) means “a woman”, not “a girl”. (This is not the case in Japanese where 男子 and 女子 mean exactly that: “a boy” and “a girl”, respectively.) However, an anagram of 女子, 子女 (zǐnǚ), means “children”, i.e. “sons and daughters”.
Many historical forms of 子 show a baby with a large head and spread arms (the legs are presumably swaddled). To remember the pronunciation of this word, I think of it as a variant of Latin letter Ƶ (pronounced American way, /ziː/ 🔊).