约量 (yāo liàng) literally means 'to measure by balance' — the character 约 (yāo) here is an archaic or specialized reading meaning 'to weigh' (distinct from its more common reading yuē, meaning 'to appoint' or 'approximately'), and 量 (liàng) means 'to measure'. Together, they form a technical noun referring to the act or result of weighing something precisely on a balance scale, especially in contexts like animal husbandry, veterinary practice, or livestock management where accurate body weight measurement is essential for health monitoring, dosage calculation, or feeding regimens.

This term is rarely used in everyday conversation but appears in agricultural handbooks, veterinary guidelines, and rural extension materials. It emphasizes precision and objectivity — unlike approximate terms like 大概 (dàgài) or 左右 (zuǒyòu), 约量 implies calibrated, instrument-based measurement. It is most frequently encountered when discussing livestock such as pigs, cattle, or poultry, where weight directly affects treatment plans and growth assessment.