A plectrum for guitars is typically a narrow, isosceles triangle with rounded corners; the most acute angle is the one used to pluck the string. A plectrum can also be called a pick (or a flatpick to distinguish it from fingerpicks). The size, shape and width may vary considerably. Thin items such as small coins, bread clippers or broken CD's can be used as substitute plectra.
Banjo and guitar players may wear a metal or plastic thumb pick mounted on a ring, and bluegrass banjo players often wear metal or plastic fingerpicks on their fingertips. Guitarists also occasionally use fingerpicks.
Guitarists in the rock, blues, jazz and bluegrass world tend to use a plectrum, partly because the use of steel strings tends to wear out the fingernails quickly, and also because using a plectrum allows for a more 'focused' and 'aggressive' sound. Many guitarists also develop the use of the plectrum and remaining right-hand fingers simultaneously, affording most of the advantages of both techniques. This technique is called "hybrid picking".
In a harpsichord, there is a separate plectrum for each string. These plectra are very small, often only about a centimeter long, about 1.5 millimeters wide, and half a millimeter thick. The plectrum is gently tapered, being narrowest at the plucking end. The top surface of the plectrum is flat and horizontal, and is held in the tongue of the jack, which permits it to pluck moving upward and pass almost silently past the string moving downward.
In the past, plectra were made of sturdy feather quills, usually from crows or ravens. In Italy, some makers (including Bartolomeo Cristofori) used vulture quills.. Other Italian harpsichords employed plectra of leather. In late French harpsichords by the great builder Pascal Taskin, peau de buffle, a chamois-like material from the hide of the European bison, was used for plectra to produce a delicate pianissimo.
"Plectrum" has both a Latin-based plural, plectra, and a native English plural, plectrums. Plectra is used in formal writing, particularly in discussing the harpsichord as an instrument of classical music. However, plectrums is more common in ordinary speech. In vernacular speech the abbreviation pleck or "plec" (plural: plecks) is sometimes used.