A boot knife or a gambler's dagger is a small fixed-blade 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...

 (usually, a dagger

Dagger

A dagger is a fighting knife with a sharp point designed or capable of being used as a thrusting or stabbing weapon. The design dates to human prehistory, and daggers have been used throughout human experience to the modern day in close combat confrontations...

) that is designed to be carried in or on a boot. Typically, such a knife is worn on a belt or under a pant leg. If worn around the neck (by means of a chain or lanyard) they become a neck knife

Neck knife

A Neck knife is a small fixed-blade knife which is carried by means of a "pendant rig", in which the knife is suspended from around one's neck, handle down, by either a length of paracord or, more commonly, a breakaway beaded or ball chain such as those utilized for military dog tags...

. Boot knives generally come with a sheath that includes some form of a clip. Most have double-edged blades, like a dagger

Dagger

A dagger is a fighting knife with a sharp point designed or capable of being used as a thrusting or stabbing weapon. The design dates to human prehistory, and daggers have been used throughout human experience to the modern day in close combat confrontations...

, that range from 3 to 5 inches (7.62 to 12.7 cm).

Legal issues

A boot-knife carries with it a multitude of legal issues, as each defining factor is likely to cause legal trouble in certain jurisdictions. Some regions prohibit carrying fixed-blade knives, double edged knives(dirk or dagger),or concealed knives.

Manufacturers

Boot knives have been made by companies such as Blackjack Knives, Ek Knives, Valor Cutlery, Gerber Legendary Blades

Gerber Legendary Blades

Gerber Legendary Blades is a maker of consumer knives and multitools headquartered in Tigard, Oregon, United States, within the Portland metropolitan area. Currently Gerber is a sub-division of Fiskars Brands Inc, owned by the Fiskars company of Finland...

, Kershaw Knives

Kershaw Knives

Kershaw Knives is a multinational corporation that designs and manufactures a range of knives, including kitchen cutlery, pocket knives, and outdoor knives...

, Parker Brothers

Parker Brothers

Parker Brothers is a toy and game manufacturer and brand. Since 1883, the company has published more than 1,800 games; among their best known products are Monopoly, Cluedo , Sorry, Risk, Trivial Pursuit, Ouija, Aggravation, and Probe...

, and Cold Steel

Cold Steel

Cold Steel is a Ventura, California-based maker of knives, swords and other edged weapons and tools. Cold Steel was founded in 1980 by company president, Lynn C. Thompson...

.