Specification refers to a detailed, precise description of the requirements, features, and characteristics of a product, system, or process. It serves as a guideline for design, development, and quality assurance, outlining what needs to be achieved to meet the intended purpose. Specifications can vary in complexity and may include technical documents, standards, or criteria that need to be fulfilled. They are essential for ensuring consistency, quality, and compliance in various fields, including engineering, software development, and manufacturing.