For instance, a vertical outlet behind an appliance or piece of furniture may give you no access points, while a horizontal ...

For instance, if you stack uniform storage boxes along a shelf in the kitchen: Is that horizontal or vertical storage? If you're hanging floating shelves on an empty wall to utilize that vertical ...

Just as car engines have flat-plane and cross-plane crankshafts like the Ford Voodoo and Coyote engines, respectively, there are also two types of smaller engines: horizontal and vertical shaft.