Memory is a modification of consciousness allowing one to recapitulate past experiences. This very truth is clearly stated in the eleventh yoga sutra of Patanjali Yoga, Known as the Anubhuta visaya asampramosah smrtih, this yoga sutra says that Memory is the unmodified recollection of words and experiences.

anubhuta perceived, apprehended, experienced, knowledge derived from direct perception, inference and comparison, verbal knowledge
visaya an object, a sense of object, an affair, a transaction
asampramosah not allowing to slip away, without stealing from anything else
smrtih memory of a thing experienced, recollection of words or experiences

Memory is the unmodified recollection of words and experiences.

Memory is a modification of consciousness allowing one to recapitulate past experiences.

Memory is the collection of the modulations and impressions of accurate knowledge, perverse knowledge, illusory knowledge and sleep. As perception changes, memory too may vary, but when correctly used, it enables one to recall experiences in their true, unspoiled state. This ability is the groundwork of the practice of discrimination.

The five properties of consciousness can be equated with the five fluctuations of consciousness - dullness with nidra, negligence with viparyaya, agitation with vikalpa, one-pointed ness with smrti and self-discipline or control with pramana.