1
general::
in the past
at a time before now, especially a long time ago:
• In the past, most children didn’t go to school at all. • We had a big argument, but it’s all in the past now.
in those days/in the old days
a long time ago in your life, or in your parents’ or grandparents’ lives, when things were different:
• £5 was a lot of money in those days. • In the old days, only very rich people had cars.
at one time
used for saying that something was true in the past, but is not now:
• At one time there were six schools in the village. • I would have agreed with you at one time.
back in the day
informal used when you are talking about a time in the past, especially one that you remember as being very good:
• I loved Blondie back in the day. • Back in the day, everyone would meet at the boys’ club.
Longman-Thesaurus