Functional design process.A program that specializes in efficient data storage and retrieval.A function that operates on functions.A collection of services.A function that calls itself, typically with a guard condition that prevents infinite execution.A smell is a term for an instinct that something is wrong.Simple set of manual tests that will quickly expose fatal errors.Criteria for a logic system.A test that exercises the smallest unit of publicly exposed code. 
Dan's Software Engineering Handbook