The term in vitro is a Latin term that means “in glass” in the English language. In vitro refers to the process of carrying out biological procedures or studies or reactions outside the body of a living organism, in an artificial and controlled environment, such as in a laboratory apparatus or vessel made of glass or any other material. A simple example of an in vitro procedure or in vitro technique is in vitro fertilization, which involves carrying out the fertilization of egg by sperm in a laboratory, for example, in a test tube (test tube baby). Another example of in vitro studies includes growing and maintaining living cells in laboratory (cell culture). To fully appreciate the meaning of in vitro, this term may be compared with in vivo (click here, to know what is in vivo?) and in silico (click here, to know what is in silico?).