Barely touch bone from Bronze Age (5)

I believe the answer is:

graze

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'barely touch' is the definition.
'graze' can be an answer for 'touch' (thesaurus). I am not certain of the 'barely' bit.

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for graze that I've seen before include "Bark (shin)" , "just kiss?" , "Feed in meadow" , "Get one's oats" , "Eat leaves" .)

I've seen this clue in the Irish Times.

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