Select all objects in the target set that intersect any object in the source / argument box set. Objects intersect if objects from both sets have some parts in common (excluding intersections consisting of common boundary coordinates only) and also have some parts not in common. Excluded, therefore, are cases where objects are entirely contained within other objects, or where some objects entirely contain others.
Suppose we have a saved selection called Durango that selects the province of Durango in Mexico.
Running Select Intersecting selects three lines that are partially inside Durango. Note that it does not select the two points and line that are entirely within Durango.
Select Adjacent to
Select Contained / Containing