IEC 63041-1:2017 applies to piezoelectric sensors of resonator, delay-line and non‑acoustic types, which are used in physical and engineering sciences, chemistry and biochemistry, medical and environmental sciences, etc. The purpose of this document is to specify the terms and definitions for the piezoelectric sensors, and to make sure from a technological perspective that users understand the state‑of-art piezoelectric sensors and how to use them correctly.