1. To originate in and continue on from some previous point or period in time. The traditional ceremony reaches all the way back into the founding of the country. The recipe I'm using reaches back into the days of the settlers.

2. To draw from, contain elements of, or be inspired by some previous period in time or someone or something therefrom. The singer reaches back into the powerhouses of the '70s to delivery some truly funky tunes. Her latest film reaches back into the black-and-white era while creating something wholly original.