bottomside

Bottomside is a directional term used to describe the underside or lower face of an object or surface. It functions as both a generic descriptive phrase and, in some cases, as a proper noun in local place names. The precise meaning depends on context, but it generally contrasts with the top side or the upper surface.

In electronics and manufacturing, bottom side refers to the side of a printed circuit board or wafer that faces away from the observer or toward the mounting surface. Bottom-side components are placed on the underside of a PCB, and features such as labels or copper patterns may be oriented or mirrored relative to the top side. In PCB design, the bottom layer is commonly referred to simply as the bottom layer or designated as a reverse-side layer in design software.

Geographically, Bottomside is used as a toponym in some regions, denoting a district or neighborhood located on the lower portion of a town, city, or along a river or hillside. The exact status and boundaries of such places vary by country and locality, and the name may arise from historical or topographic factors.

In common usage, bottomside may appear in reference to the underside of items like packaging, clothing, or devices. When capitalized as a place name, it is treated as a proper noun. Related terms include top side and underside, which describe opposing orientations.