约度 (yāo dù) is a formal verb meaning 'to verify measurement' or 'to calibrate' — especially in technical, medical, or scientific contexts where precision is critical. The character 约 (yāo) here carries the sense of 'to bind,' 'to specify,' or 'to standardize,' while 度 (dù) means 'measurement' or 'scale.' Together, they convey the idea of confirming or adjusting a measuring instrument or procedure to ensure accuracy against a known standard.

This term is commonly used in healthcare settings (e.g., verifying blood pressure device accuracy), laboratory protocols, quality control processes, and metrology. It is not used in everyday conversation; instead, it appears in professional documentation, regulatory guidelines, or technical training. Unlike more general terms like 测量 (cèliáng, 'to measure'), 约度 specifically emphasizes validation and traceability — ensuring measurements align with authoritative references.