EBE stands for Extra-terrestrial Biological Entity. The word was probably first used in 1949 when a surviving crew member of a crashed UFO was found near Roswell, New Mexico. (A minority of sources claim that a first survivor was already found after a crash in 1947).
When more crash survivors were found at subsequent crash sites, and when the US Government started exchanging 'ambassadors' with alien civilisations, the designations were changed to EBE-1, EBE-2, etc.
After a while these types of designations were abandoned.
This topic was copied from the HyperBase and is likely to be revised.