This Filipino word derives from the Spanish word hermana, meaning sister.
Filipinos use this word as a familiar term for a woman in her 40's or thereabouts even if not related to her. She could be the maid, the woman at a store you go to everyday...
Nasaan si Manang?
Where is Manang?
Nakita mo ba si Manang?
Have you seen Manang? Do you know where Manang is?
A popular Ilocano folk song has the title Manang Biday. The name of the woman is Biday.