A paper knife or letter opener is a knife

Knife

A knife is a cutting tool with an exposed cutting edge or blade, hand-held or otherwise, with or without a handle. Knives were used at least two-and-a-half million years ago, as evidenced by the Oldowan tools...

-like object used to open envelope

Envelope

An envelope is a common packaging item, usually made of thin flat material. It is designed to contain a flat object, such as a letter or card....

s or to slit uncut pages of books. Electric versions

Consumer electronics

Consumer electronics are electronic equipment intended for everyday use, most often in entertainment, communications and office productivity. Radio broadcasting in the early 20th century brought the first major consumer product, the broadcast receiver...

 are also available, which work by using motors

Electric motor

An electric motor converts electrical energy into mechanical energy.Most electric motors operate through the interaction of magnetic fields and current-carrying conductors to generate force...

 to slide the envelopes across a blade

Blade

A blade is that portion of a tool, weapon, or machine with a cutting edge and/or a pointed tip that is designed to cut and/or puncture, stab, slash, chop, slice, thrust, or scrape animate or inanimate surfaces or materials...

. These have the advantage of being able to handle a greater volume of envelopes, but the blade can slice into the contents of the envelope and damage them.

Letter openers may be composed of wood

Wood

Wood is a hard, fibrous tissue found in many trees. It has been used for hundreds of thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers embedded in a matrix of lignin which resists compression...

, metal

Metal

A metal , is an element, compound, or alloy that is a good conductor of both electricity and heat. Metals are usually malleable and shiny, that is they reflect most of incident light...

, plastic

Plastic

A plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...

, sometimes even ivory

Ivory

Ivory is a term for dentine, which constitutes the bulk of the teeth and tusks of animals, when used as a material for art or manufacturing. Ivory has been important since ancient times for making a range of items, from ivory carvings to false teeth, fans, dominoes, joint tubes, piano keys and...

, or a combination of materials. Some modern openers have a hidden razor blade

Razor blade

Razor blade may refer to* A razor* The Razor Blade, a 1920s racing car* Razor blade steel, a type of steel originally designed specifically for razor blades...

 inside a plastic handle.
Robert Stewart (Viscount Castlereagh)

Robert Stewart, Viscount Castlereagh

Robert Stewart, 2nd Marquess of Londonderry, KG, GCH, PC, PC , usually known as Lord CastlereaghThe name Castlereagh derives from the baronies of Castlereagh and Ards, in which the manors of Newtownards and Comber were located...

 committed suicide with a pen knife, not a letter opener (as both his article and this page previously erroneously stated), in 1822.

Patrick Henry's letter opener

Patrick Henry

Patrick Henry

Patrick Henry was an orator and politician who led the movement for independence in Virginia in the 1770s. A Founding Father, he served as the first and sixth post-colonial Governor of Virginia from 1776 to 1779 and subsequently, from 1784 to 1786...

 is famous for making a speech before the Virginia

Virginia

The Commonwealth of Virginia , is a U.S. state on the Atlantic Coast of the Southern United States. Virginia is nicknamed the "Old Dominion" and sometimes the "Mother of Presidents" after the eight U.S. presidents born there...

 House of Burgesses

House of Burgesses

The House of Burgesses was the first assembly of elected representatives of English colonists in North America. The House was established by the Virginia Company, who created the body as part of an effort to encourage English craftsmen to settle in North America...

 on March 23, 1775, stating the famous words "Give me Liberty, or give me Death!

Give me Liberty, or give me Death!

"Give me Liberty, or Give me Death!" is a quotation attributed to Patrick Henry from a speech he made to the Virginia Convention. It was given on March 23, 1775, at St. John's Church in Richmond, Virginia, and is credited with having swung the balance in convincing the Virginia House of Burgesses...

" After this, he pretended to plunge a letter opener into his chest.