Legacy System

Noun · Development

Definitions

  1. An older software system still in production use, often built on outdated technology, poorly documented, and difficult to modify — but too critical or costly to replace. Legacy systems frequently outlive their original developers and become organizational knowledge bottlenecks.

    In plain English: An old but still essential computer system that everyone is afraid to touch because it is hard to understand and risky to change.

    Example: "The billing logic is trapped in a legacy COBOL system from 1997, and the one person who understood it retired last year."

Related Terms