The term "mid-thirties" refers to the age range between 33-36. It can be used to describe a person's age or the time period in which they are living. While "mid-thirties" is a common phrase, there are several synonyms that can be used to describe this age range. These include the phrases "in one's prime," "in the thick of it," or "mid-career." Other phrases that can be used to describe this age range include "approaching middle age," "thirty-something," or "midway through one's thirties." Depending on the context, any of these phrases can be a suitable alternative to "mid-thirties".