Since the 16th Century, when words first became mass-printable, there has been a need for typeface, and since about that time, printers have been expressing themselves with that form. We even prominently use the same system of sizing, in what we still call "points," which was taken from the original, expressed as the amount of parts out of 72 which it was of a full inch. Fonts are still largely produced by foundries, which can justifiably be protective of their intellectual property, but more and more fonts are being produced by independent artists and typographers. The term font originally applied to the different sizes of letters that typesetters would have of the same style of letter, which altogether compiled a “typeface”. Since computer technology, most of us have come to think of a font as the whole typeface.
Kerning is the process of moving a glyph, either manually or automatically closer to a juxtaposed letter. The process generates from when printing presses needed letters closer together than a solid block would otherwise allow. The printers had special blocks created over which part of the letter would hang, and fit under a neighboring glyph block. The piece of metal hanging out was called a “kern”. Today many foundries and typeface designers include a certain amount of automatic kerning into their designs. The rendering system uses each glyph and the glyphs immediately following that letter to find if this pair exists as something different than simply the first glyph alone. So kerned pairs are placed before that glyph in the glyph generation programming of that font. Some formats now, though, in order to take up less data space, simply group letter into the same roles for whether they’re the first letter or the second, and from there determine how close the second letter in the pair should be moved back toward the first.