eUICC
The secure chip inside an eSIM device that can store several operator profiles and switch between them.
eUICC stands for embedded Universal Integrated Circuit Card. It is the hardware that makes remote SIM provisioning possible, following GSMA specifications.
Why it matters for business
Ask suppliers which GSMA specification their eUICC supports (for IoT, SGP.32 is the newest), because it decides how and by whom profiles can be changed.