compounding

Compounding is the act of combining two or more substances or factors to create a whole with new properties. The term is used across disciplines, each with its own methods, purposes, and standards. In everyday use, compounding can refer to financial growth, pharmaceutical preparation, chemical synthesis, or word formation.

In finance, compounding describes earning interest on previously accrued interest. The amount grows according to the compounding period and rate. The formula A = P(1 + r/n)^{nt} applies for periodic compounding. More frequent compounding yields higher returns or higher debt charges. Continuous compounding uses e^{rt}.

In pharmacy and healthcare, compounding is the custom preparation of medications to meet an individual patient's needs, such as adjusting dosage, removing allergens, or changing formulation. Compounding can be sterile or non-sterile. It is subject to professional standards, quality control, and regulatory oversight; many jurisdictions require safe practice and documentation.

In chemistry, a compound is a substance formed from two or more elements bonded chemically in fixed ratios. Compounds have properties distinct from their constituent elements. Most compounds have names reflecting their composition, and their formation is described by chemical equations and stoichiometry.

In linguistics, compounding is the process of forming a new word by combining two or more independent words or stems, such as notebook or sunflower. The extent of affixation, phonological changes, and semantic blending varies by language. Compounding contributes to vocabulary growth and sometimes to ambiguity.