The term "headstock" is one of those words that has come to have completely different meanings depending on the context in which it is used. If you look up this word in the dictionary, you find "a bearing or pedestal of a revolving or moving part." However, if you it up in reference to its use in guitar terminology, you find that it refers to the bulbous portion used to hold the strings at the end of a guitar neck. Clearly, the two meanings have little to do with each other, the only connection being the machine heads usually affixed to guitar headstocks (more on this later). Like so many words in the English language, "headstock" is undergoing a transformative process, one being driven by its usage in everyday life.

As mentioned, the main purpose of a guitar headstock is to hold the strings of the instrument. Headstocks are outfitted with multiple machine heads (or turners, gear heads or tuning machines) to which the strings are attached, the ratio being one string per head. A guitar is tuned by the adjustment of the machine heads, which govern the tension of the strings and as a result, the sound the strings produce. The machine heads are usually laid out in either a "3+3" pattern or a "6 inline" pattern, although there are many other combinations and possibilities. The desired layout of the machine heads and the shape of the headstock (more on this later) are directly linked.

The configuration of the headstock in relation to the guitar's neck comes in two styles: straight and angled. In the first style, the headstock forms a single plane with the surface of the neck. Guitars with such headstocks are easier to manufacture, as they can be created from a single piece of wood. Angled headstocks, on the other hand, form an acute angle of varying degrees with the guitar's neck. The range of this angle is significant, anywhere from 3 degrees to 25 degrees. It is interesting to note the amount of discussion surrounding this topic, all due to the debate of which angle produces the best tone and stability. Different guitar manufacturers are renowned for using different angles on different models, and each maintains that their angle produces optimum results.

In addition to their substantive qualities, headstocks also provide a convenient palette upon which guitar manufacturers can advertise. Company logos are frequently inlaid into the surfaces of guitar headstocks, often in eye-catching materials like mother of pearl, abalone, ivory or exotic colored wood. Interestingly, the shape or outline of the headstock has also become a brand-associated characteristic. Although there is no technical legal reason, major guitar manufacturers each use their own shape when it comes to headstocks and never copy that of a competitor.

Companies like Fender, Gibson, ESP and Richenbacker all use signature outlines for their various guitar headstocks. As mentioned, the shape used has a direct correlation to the machine head layout the luthier intends to install. Those with the 3+3 pattern are often slightly wider and more symmetrical, while those with the 6 inline pattern tend to be longer and are often pointed.