Food for three people in a nut shell? (9)
I believe the answer is:
nutriment
'food' is the definition.
(I know that nutriment is a type of food)
'people in a nut shell?' is the wordplay.
'people' becomes 'men' (men are people).
'in' indicates putting letters inside.
'shell?' becomes 'rit' (I can't explain this - if you can you should give a lot more credence to this answer).
'nut'+'rit'='nutrit'
'men' going into 'nutrit' is 'NUTRIMENT'.
'for three' is the link.
This may not be right. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for nutriment that I've seen before include "diet" , "Nourishing food" , "It sustains" , "Material providing food" , "Sustenance, nourishment" .)