Cách sử dụng
"cid" is not a commonly used word in English. It is often used as an abbreviation for "acid" in chemistry, such as hydrochloric acid (HCl). It can also refer to the identification number assigned to a criminal case, known as a "CID number." In everyday conversation, it is unlikely that you will encounter the word "cid" very often, so it's not necessary to focus on it too much.