Immemorial is an adjective that means extending beyond the reach of memory.

The Latin word memorialis (mem or ee AL ees) roughly translates to ‘memory.’ With the prefix I-M, we get a word that means ‘lacking memory.’ Our word of the day is used to refer to something ‘beyond memory.’ For example: There is something immemorial about the tribal rhythms we heard at the shore. They seemed like echoes from the ancient past.