x1 is a mereological object which overlaps with mereological object x2 via at least object x3 in universe of discourse x4.
There exists an object y in x4 such that y is a part of x1, and y is a part of x2; moreover, x3 is such a y. Sometimes, this definition is restricted so that objects which are parts of all things in the universe are not candidates for y. See also: "pagbrjonlapi", "pagbu", "klesrverlapi".