Saw in this time and era (5)
I believe the answer is:
adage
'saw' is the definition.
(saw can mean a proverb or saying)
'time and era' is the wordplay.
'time' becomes 'AD' (AD, Anno Domini, as opposed to BC, Before Christ).
'and' means one lot of letters go next to another.
'era' becomes 'age' (both can mean a long period of time).
'ad'+'age'='ADAGE'
'in this' is the link.
(Other definitions for adage that I've seen before include "Old saw" , "Proverb expressing a general truth" , "Old saying, maxim" , "Proverb, maxim" , "Old saying; proverb" .)