Gherkin

Gherkin is a business-readable domain-specific language, which is intended for specifying and documenting software requirements.

Gherkin specifies a software system on a feature-by-feature basis from the point of view of different groups of users. The objective is to provide a unified specification that can be written and understood by technical and non-technical people alike. As such, Gherkin provides a common language for product managers and developers to discuss and document the business requirements.

Gherkin provides an executable specification format. The language can be parsed by machines and used as the basis for automated acceptance testing.

Example
In order to be confident in my purchases
As a Buyer
I want to receive refunds for faulty goods

Scenario: Jeff returns a faulty microwave
  Given Jeff has bought a microwave for $100
  And he has a valid receipt
  When he returns the microwave
  Then Jeff should be refunded $100

The Gherkin language was originally developed as part of the Cucumber testing framework, but it has since been adopted by other testing frameworks including SpecFlow, Behat, JBehave, and Lettuce.

See TS2: Requirements Specifications in my technical standards.