Article covering my small fruits (6)
I believe the answer is:
acorns
'fruits' is the definition.
(acorn is a kind of fruit)
'article covering my small' is the wordplay.
'article' becomes 'an' (indefinite article).
'covering' means one lot of letters goes inside another.
'my' becomes 'cor' (both are expressions of surprise).
'small' becomes 's' (abbreviation - e.g. clothes size).
'an' going around 'cor' is 'acorn'.
'acorn'+'s'='ACORNS'
(Other definitions for acorns that I've seen before include "nuts" , "From which great oak trees grow" , "Seeds of the oak" , "Fruits of the oak tree" , "From which 23 down grow" .)