One feeding relative rice, for example (5)
I believe the answer is:
Here is my best explanation:
'rice for example' is the definition.
(rice is a kind of grain)
'one feeding relative' is the subsidiary indication.
'one' becomes 'i' (roman numeral).
'feeding' means one lot of letters goes inside another.
'relative' becomes 'gran' (I've seen this in other clues**).
'i' going into 'gran' is 'grain'.
(Other definitions for grain that I've seen before include "Single piece of sand etc", "Sand particle", "Small particle - weight", "Cereal as food", "Particle of e.g. sand", "Small hard particle of anything", "Texture of wood", "Enter into combat with", "Cereals" and "Small particle - wood texture".)