A "point" (abbreviated as "pt") is a unit of measurement commonly used in typography and desktop publishing to specify the size of text, fonts, and other elements on a printed or digital page. The point is part of a system of measurement used in the field of typesetting, which involves arranging and designing text for printed materials.
In the point system:
1 point (abbreviated as "pt") is equal to approximately 1/72nd of an inch. This means that there are approximately 72 points in 1 inch.
Points are used to define the size of fonts, leading (line spacing), and other layout details in printed materials. For example, when you specify a font size of 12 points, you are indicating that the height of the characters in that font will be roughly 1/6th of an inch or about 4.23 millimeters.
Points are still widely used in the design and printing industry, especially when specifying font sizes, line spacing, and other layout details for printed materials like books, magazines, and newspapers. In digital design and modern desktop publishing software, you can often switch between using points and other units like picas, inches, millimeters, or pixels to set and adjust the layout of text and graphic elements.
"Caliber" is a term used to describe the internal diameter or bore of a firearm's barrel or the diameter of the projectile (bullet) it fires. It is typically expressed in either inches or millimeters, depending on the measurement system used.
In the United States, caliber is often expressed in inches. For example, a firearm with a bore diameter of 0.30 inches would be referred to as having a ".30 caliber" bore. Similarly, a firearm with a bore diameter of 0.45 inches would be described as having a ".45 caliber" bore.
In many other countries that use the metric system, caliber is expressed in millimeters. For instance, a firearm with a bore diameter of 9 millimeters is referred to as having a "9mm caliber" bore.
Caliber is an essential specification for firearms because it determines the size of ammunition that can be used with a particular gun. The ammunition for a firearm must match its caliber to function safely and accurately. Different firearms are designed to use specific calibers of ammunition, and it's crucial for firearm owners to select and use the correct ammunition for their guns.