The period of indeterminacy associated with an indeterminate event is an anchored duration that delimits the range of possible times during which the event occurred. The event happened sometime during the period of indeterminacy but it is unknown exactly when. An anchored duration is usually referred to as an interval, however, in this context, we prefer to call it a period because the syntactic difference between an ``indeterminate interval'' and an ``interval of indeterminacy'' is slight, while the semantic difference is great. Hence, while using ``interval of indeterminacy'' might be more precise (+E9), it would also be more confusing (-E8). Using ``fuzzy interval'' would also be confusing due to the influence of fuzzy databases (+E5).