Latin period (4,6)
I believe the answer is:
anno domini
'latin period' is the definition.
The definition suggests a singular noun which matches the answer. I also know that 'latin' relates to this answer.
This is all the clue.
Can you help me to learn more?
(Other definitions for anno domini that I've seen before include "Advancing old age (informal)" , "AD in full" , "later days" , "In the year of our Lord" , "having a date, she may put it on" .)