o·ver·lap 
(ō′vər-lăp)
(ō′vər-lăp)v. o·ver·lapped, o·ver·lap·ping, o·ver·laps
v.tr.
1. To lie or extend over and cover part of.
2. To have an area or range in common with.
v.intr.
1. To lie over and partly cover something.
2. To correspond in character or function: Their duties overlap.
3. Mathematics To have one or more elements in common. Used of sets.
n. (ōvər-lăp′)
1. A part or portion that overlaps or is overlapped.
2. An instance of overlapping.