There's wood in the strange piece of armour (6)
I believe the answer is:
helmet
'armour' is the definition.
(I know that helmet is a type of body armor)
'there's wood in the strange piece' is the wordplay.
I cannot quite understand how this works, but
'wood' could be 'elm' (elm is a type of tree) and 'elm' is found in the answer.
an anagram of 'the' is 'het' which is within the remaining letters.
No letters remain.
This explanation may well be incorrect...
'of' is the link.
Can you help me to learn more?
(Other definitions for helmet that I've seen before include "Protective hat" , "personal protection" , "Protective covering for head of motor-cyclist" , "Head protection" , "Protective casing for the head" .)