In Mandarin Chinese, 米 (Pinyin: mǐ 🔊) means “rice”. Another, quite unrelated, meaning is “metre” (a base unit of length in the International System of Units), a phonetic approximation of an English loanword.
We’ve already met this symbol as a part of traditional character 氣 (qì). Uncle Hanzi says that originally 米 represented a spike of rice. From the modern shape, it’s difficult to say. Given that rice was the staple food in China for millennia, one can imagine that a simple but widely recognisable symbol was in order to conduct everyday business — for example, to jot down how many portions of rice have been ordered.
More photos of rice @ Shutterstock.