D defs.my
Entry 5 senses Webster, 1913

Formula

/fôr'-myəl-ə/ · For·mu·la · IPA /ˈfɔɹ.mjə.lə/
01 n. A prescribed or set form; an established rule; a fixed or conventional method in which anything is to be done, arranged, or said.
pl. Formulas, Formulæ ((#))
  1. 1.
    A prescribed or set form; an established rule; a fixed or conventional method in which anything is to be done, arranged, or said.
  2. 2.
    A written confession of faith; a formal statement of foctrines.(Eccl.)
  3. 3.
    A rule or principle expressed in algebraic language; as, the binominal formula.(Math.)
  4. 4.
    A prescription or recipe for the preparation of a medicinal compound.(Med.)
  5. 5.
    A symbolic expression (by means of letters, figures, etc.) of the constituents or constitution of a compound.(Chem.)
Phrases & compounds
Empirical formula — an expression which gives the simple proportion of the constituents; as, the empirical formula of acetic acid is C2H4O2.
Graphic formula — an expression of the constitution, and in a limited sense of the structure, of a compound, by the grouping of its atoms or radicals; as, a rational formula of acetic acid is CH3.(C:O).OH; -- called also structural formula, constitutional formula, etc. See also the formula of Benzene nucleus, under Benzene.
Molecular formula — a formula indicating the supposed molecular constitution of a compound.