Does the CRA use or define the term "over-the-air update"?
No.
The CRA speaks about security updates, automatic security updates where applicable, and mechanisms to securely distribute updates. It does not create a separate legal definition of "over-the-air" or "OTA".
The ETSI smart-device standards in the local CRA corpus do use the term OTA for updates delivered over a network interface. So, in CRA practice, OTA is best understood as one possible way to implement the CRA's update obligations, not as a separate legal category.
Annex I Part I point (2)(c), Annex I Part II point (7)
term "OTA"