Such tablets can be taken in pairs (7)
I believe the answer is:
aspirin
'such tablets can' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'taken in pairs' is the wordplay.
'in pairs' anagrams to 'ASPIRIN'.
Though, I'm unsure how the anagram is indicated.
'be' is the link.
Can you help me to learn more?
(Other definitions for aspirin that I've seen before include "Commonly used pain-killer" , "Common pain tablet" , "number" , "Common painkiller" , "Pain-relieving tablet" .)