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 they are linked in a way I don't understand?
'taken in pairs' is the wordplay.
'in pairs' can be anagrammed to 'ASPIRIN'.
Though, I'm not clear how this 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" .)