noun pl. formulas -·las or formulae -·lae′ (-lē′, -lī′)

1. a fixed form of words, esp. one that has lost its original meaning or force and is now used only as a conventional or ceremonial expression “Very truly yours” is a formula used in letters
2. a rule or method for doing something, esp. when conventional and used or repeated without thought a formula for musical comedies
3. an exact statement of religious faith or doctrine
4. 1. directions for preparing a medicine, a paint, a baby's food, etc.
   2. something prepared from such directions; often specif., a milk preparation for feeding a baby
5. a set of algebraic symbols expressing a mathematical fact, principle, rule, etc. A = πr is the formula for determining the area of a circle
6. Chem. an expression of the composition of a compound (or a radical, etc.) by a combination of symbols and figures to show the constituents

Etymology: L, dim. of forma, form

adjective