In days past is a phrase used to refer to a time in the past, usually a long time AGO. The crossword solutions for this phrase are ONCE (4 letters), AGO (3 letters), and ATONETIME (9 letters). ONCE is an adverb meaning at one time or formerly. AGO is an adverb meaning before the present time. ATONETIME is an adverb meaning at one time or formerly. Together, these three words can be used to describe a time in the past.