What term describes an interval of time between events or periods?

The term that describes an interval of time between events or periods is "interim." This word is often used to signify a temporary period or arrangement that exists between two defined situations or activities. In various contexts, such as in business or project management, an interim phase serves to fill the space until a more permanent condition is established or to indicate a transitional period between two significant events.

The other options, while they do relate to interruptions or intervals, do not specifically imply the same structured period of time associated with transitioning from one event to another. "Gap" suggests a space or interruption but lacks the connotation of a temporary interval defined by events. "Pause" indicates a temporary stop but does not emphasize the element of time between distinct periods. "Break" refers to a pause or interruption but is typically more casual and does not denote the transitional nature of time between two events as effectively as "interim" does.