grandmother
noun /ˈɡrænmʌðə(r)/
  /ˈɡrænmʌðər/
Idioms - the mother of your father or mother
- I always loved going to visit my grandmother.
 
 
Idioms 
teach your grandmother to suck eggs 
- (British English, informal) to tell or show somebody how to do something that they can already do well, and probably better than you can