Overlap

Webster's Dictionary of the English Language

·vt & ·vi To lap over; to Lap.

II. Overlap ·noun The lapping of one thing over another; as, an overlap of six inches; an overlap of a slate on a roof.

III. Overlap ·noun An extension of geological beds above and beyond others, as in a conformable series of beds, when the upper beds extend over a wider space than the lower, either in one or in all directions.