I am fairly certain it is the rifled part of the barrel, not including the chamber, from the headspace ledge to the muzzle, and including any permanant non-rifled attachments to the muzzle. Therefore, a rifle with a fifteen inch barrel can be legal if it has a muzzle brake or compensator which brings its length to over sixteen inches.
It is approximately equal the length of your foot, if measured from the crease of your elbow to the crease of the wrist with your arm straight down
State law may provide an even more stringent standard, but in no case is it allowable to violate the minimum overall length mandated by the Federal Firearms Act.A short barreled rifle is defined in the US Code, Title 18, Part I, Chapter, Sec. 921. as follows...(8) The term ''short-barreled rifle'' means a rifle having one or more barrels less than sixteen inches in length and any weapon made from a rifle (whether by alteration, modification, or otherwise) if such weapon, as modified, has an overall length of less than twenty-six inches.
Based on what information? Since this part is usually easiest to measure, it is usually measured, and other things, like the cubes area and volume, are then calculated based on the length.
To convert from the optical absorption length (α) in inverse centimeters to the imaginary part (κ) of the refractive index, you can use the formula κ = λ / (4πα), where λ is the wavelength of light. This formula relates the absorption length to the imaginary part of the refractive index at a specific wavelength.
The length of a forearm would be more of a phenotype, as it is a physical characteristic that can be observed and measured. Genotype refers to the genetic makeup of an individual, which may influence the phenotype but doesn't directly determine the length of a specific body part.
The part of a line with two endpoints that can be measured is called a line segment. Unlike an infinite line, a line segment has a definite length because it is bounded by its endpoints. This makes it possible to calculate the distance between the two points, providing a measurable quantity.
powder
On a rifle, it is the part of the rifle your non-dominant hand holds to steady the barrel.
Part of a pound.
Legal part of speech is Verb, Noun, and Adjective
Depends on the exact weapon
Part of the manufacturing process for the barrel.