Lamen is a general term for a magical pendant

Pendant

A pendant is a loose-hanging piece of jewellery, generally attached by a small loop to a necklace, when the ensemble may be known as a "pendant necklace". A pendant earring is an earring with a piece hanging down. In modern French "pendant" is the gerund form of “hanging”...

 worn around the neck so that it hangs upon the breast over the heart. Its uses vary but generally is a commandment of authority. The magician wears a lamen which is a symbolic representation of his relation to his godhead. He will wear lamens made of the sigils

Sigil (magic)

A sigil is a symbol created for a specific magical purpose. A sigil is usually made up of a complex combination of several specific symbols or geometric figures, each with a specific meaning or intent.- Name and origin :...

 of spirits he wishes to command. It has been described as "a sort of Coat of Arms. It expresses the character and powers of the wearer." One type of lamen is the talisman

Amulet

An amulet, similar to a talisman , is any object intended to bring good luck or protection to its owner.Potential amulets include gems, especially engraved gems, statues, coins, drawings, pendants, rings, plants and animals; even words said in certain occasions—for example: vade retro satana—, to...

 which functions as a storehouse of some particular kind of energy, the kind that is needed to accomplish the task for which you have constructed it.

The Pentacle

Pentacle

A pentacle is an amulet used in magical evocation, generally made of parchment, paper or metal , on which the symbol of a spirit or energy being evoked is drawn. It is often worn around the neck, or placed within the triangle of evocation...

 is often confused with both the others; it is also called a "Minutum Mundum", "the Universe in Little".

Various Magical Orders used Lamen, including Ordo Templi Orientis

Ordo Templi Orientis

Ordo Templi Orientis is an international fraternal and religious organization founded at the beginning of the 20th century...

 and Hermetic Order of the Golden Dawn

Hermetic Order of the Golden Dawn

The Hermetic Order of the Golden Dawn was a magical order active in Great Britain during the late 19th and early 20th centuries, which practiced theurgy and spiritual development...

. They were used to mark members just as secret handshake

Secret handshake

A secret handshake is a distinct form of handshake or greeting which conveys membership in or loyalty to a club, clique or subculture. The typical secret handshake involves placing one's fingers or thumbs in a particular position, one that will be recognized by fellow members while seeming to be a...

s have been used throughout the ages.