A clipboard is a thin, rigid board

Board

-Flat surface:* Lumber, or other rigid material, milled or sawn flat** See :Category:Engineered wood** Cutting board** Sounding board, of a musical instrument* Cardboard* Paperboard*Corrugated fiberboard*Fiberboard*Particle board, also known as chipboard...

 with a clip at the top for holding paper in place. A clipboard is typically used to support paper with one hand while writing on it with the other, especially when other writing surfaces are not available.

Other uses

Another use that was typical before the era of personal computers (which brought about word processing and computer graphics) was to hold pieces of text and art that had been clipped with scissors

Scissors

Scissors are hand-operated cutting instruments. They consist of a pair of metal blades pivoted so that the sharpened edges slide against each other when the handles opposite to the pivot are closed. Scissors are used for cutting various thin materials, such as paper, cardboard, metal foil, thin...

 from one sheet of paper to be pasted with paste

Adhesive

An adhesive, or glue, is a mixture in a liquid or semi-liquid state that adheres or bonds items together. Adhesives may come from either natural or synthetic sources. The types of materials that can be bonded are vast but they are especially useful for bonding thin materials...

 onto another sheet. This use provided the analogy and terminology for computer clipboards

Clipboard (software)

The clipboard is a software facility that can be used for short-term data storage and/or data transfer between documents or applications, via copy and paste operations...

.

Police clipboards

Many police officer

Police officer

A police officer is a warranted employee of a police force...

s carry clipboards. Police clipboards are designed for constant use, and have one or two compartments designed for filing documents and reports while in police transit.