Long time is a fairly common phrase used to refer to a significant duration of time. However, there are many synonyms for long time that can be used interchangeably, depending on the context in which the phrase is used. Some of the synonyms for long time include extended period, prolonged duration, protracted length, elongated time span, lengthy interval, protracted stretch, enduring term, lasting time and extensive time lapse. These synonyms can be utilized when describing historical events, long journeys, book series, and much more. So, the next time you need to describe a significant length of time, consider using one of these synonyms instead of the phrase "long time".