OTA (Over-The-Air) - definition
Over-the-air is any method of making data transfers or transactions wirelessly using the cellular network instead of a cable or other local connection.
Most commonly, this term refers to downloading or uploading content or software (such as downloading ringtones, uploading images, etc.).
If the term is used for updating a phone's firmware this is also known as FOTA (Firmware Over-The-Air).