Often a user knows only approximately when an event happened, when an interval began and ended, or even the duration of a span. For instance, she may know that an event happened ``between 2 PM and 4 PM,'' ``on Friday,'' ``sometime last week,'' or ``around the middle of the month.'' She may know that a airplane left ``on Friday'' and arrived ``on Saturday.'' Or perhaps, she has information that suggests that a graduate student takes ``four to fifteen'' years to write a dissertation. These are examples of time indeterminacy. The adjective ``time'' allows parallel kinds of indeterminacy to be defined, such as spatial indeterminacy (+E1). We prefer ``time indeterminacy'' to ``fuzzy time'' since fuzzy has a specific, and different, meaning in database contexts (+E8). There is a subtle difference between indeterminate and imprecise. In this context, indeterminate is a more general term than imprecise since precision is commonly associated with making measurements. Typically, a precise measurement is preferred to an imprecise one. Imprecise time measurements, however, are just one source of time indeterminate information (+E9). On the other hand, ``time incompleteness'' is too general. Time indeterminacy is a specific kind of time incomplete information.