formula

A formula is a fixed pattern used to show, make, or achieve something. People often first meet the word in math or science. In math, a formula shows the relationship between quantities, such as a rule for finding area, speed, or interest. In chemistry, a chemical formula uses letters and numbers to show what a substance is made of, like $H_2O$ for water.

But the word is not limited to technical subjects. It can also mean a standard method, recipe, or plan that tends to bring the same result. A company may talk about its formula for success. A writer or filmmaker may rely on a familiar formula for telling a story. In this sense, the word can be positive, meaning reliable and effective, or slightly negative if the method feels too predictable.

There is also the very common everyday meaning of baby formula, a prepared food made for infants as a substitute for or addition to breast milk. In this use, the word refers to a carefully made mixture rather than a rule or expression.

So, the word brings together several related ideas: a symbolic expression, a tested method, a recipe-like pattern, or a prepared mixture. In each case, it suggests something arranged in a set way to produce a particular result.