A Story

婆 = grandmother, more specifically it refers to mother's mother.

婆婆, po4po4, is also a polite and respectful way to address an elderly woman in general. This would be someone whose age might appear similar to your own or who would be your grandmother's age.

The top part of the word 波 is created with water 氵and skin 皮 (pei4 sound) which combined, creates a bo1 sound. 波 is also its own character, meaning wave.
Accompanied with woman 女, it creates a po4 sound.

Characters can help indicate sound too and not just meaning.

Date Added: 3/14/2021