What is a common term used to define a specified length of time?

The term "timeline" is often used in various contexts to define a specified length of time, particularly in project management, historical contexts, or planning situations. It presents a visual representation of the sequence of events or the duration of phases over a particular timeframe. A timeline effectively marks the start and end points of specific periods, showcasing how events are related and when they occur relative to each other.

In contrast, while "duration," "period," and "interval" are related terms that refer to time dimensions, they do not specifically convey the structured approach of mapping time that a timeline offers. "Duration" typically refers to the length of time something lasts, "period" is more of a general reference to a segment of time, and "interval" often describes the distance between two points in time but doesn't imply a structured visualization of events. Therefore, "timeline" is the most appropriate term when describing a specified length of time with a focus on chronological order and context.