约重 (yāo zhòng) is a noun meaning 'approximate weight' or 'estimated weight'. It combines 约 (yāo), meaning 'approximately' or 'roughly', and 重 (zhòng), meaning 'weight' or 'heaviness'. Unlike the verb 重 (zhòng) meaning 'to be heavy' or the verb 称 (chēng) meaning 'to weigh', 约重 functions exclusively as a noun referring to the numerical value of weight when precision is not required — commonly used in informal measurements, animal husbandry, market settings, or casual descriptions.

This term appears frequently when estimating the weight of livestock, pets, or produce — for example, on farm reports, pet adoption forms, or vendor signs. It is never used as a verb (e.g., you cannot say '我约重了它'); instead, it always serves as a subject, object, or predicate noun indicating a rounded figure, often followed by units like 千克 or 斤. Its tone-sensitive pronunciation (yāo, not yuē) distinguishes it from the more common 'yuē' meaning 'to appoint' or 'to agree'.