Many sources translate "Baba" as "beloved". For instance, Yogapedia said
This mantra is used for practice of kirtan in Ananda Marga
Baba means "beloved," nam means "name" and kevalam means "only." Therefore, the mantra may be translated as "only the name of the beloved."
However, other sources claim that "Baba" (or "Babaji") is a honorific that means "Father". I haven't found any "beloved" translation variant out of the context of Ananda Marga.
Can "Baba" really be translated as "beloved"?