Crossword Genius

Baby beginning to eat solid (4)

Ross

I believe the answer is:

cube

I'm a little stuck... Click here to teach me more about this clue!

'solid' is the definition.
(I know that cube is a type of regular polyhedron)

'baby beginning to eat' is the wordplay.
'baby' becomes 'cub' (I can't explain this - if you can you should give a lot more credence to this answer).
'beginning to' says to take the initial letters.
The first letter of 'eat' is 'e'.
'cub'+'e'='CUBE'

Can you help me to learn more?

(Other definitions for cube that I've seen before include "Hexahedron with six plane faces" , "Square-faced solid" , "Form of chiller" , "Hexagonal ice" , "Cut into solid squares" .)

I've seen this clue in The Guardian.
Want a hint initially instead of a full solution? Install my app