Relative with minute piercing cut structure of tongue (10)

'tongue' is the definition.
Both the definition and answer are singular nouns.
Perhaps you can see an association between them that I don't see?

'relative with minute piercing cut structure' is the wordplay.
'relative' becomes 'mamma' (mamma is a kind of relative).
'with' means one lot of letters go next to another.
'minute piercing cut structure' becomes 'grand' (I am not sure about this - if you are sure you should believe this answer much more).
'mamma' put after 'grand' is 'GRANDMAMMA'.

'of' is the link.

Can you help me to learn more?