The term "upper limits" is often utilized to refer to the maximum point or boundary of something. However, there are multiple synonyms that can be applied to this phrase depending on the context. "Ceiling," "cap," and "top" are often used to indicate an upper limit on prices, quantities, or temperatures. In discussing financial matters, "maximum threshold" or "peak" can also be employed. In reference to physical attributes, "maximum extent" and "greatest boundaries" may serve as synonyms for "upper limits." Ultimately, the choice of which synonym to use will depend on the specific situation and the level of precision in language required.