The parts of a knife can be divided into two major parts: the blade and the handle. Each of the common component parts of the blade and the handle are described below.
The blade of a knife is constructed by either forging or cut from stamped steel.
Forged knives are made by heating a bar of steel until softened and dropping the steel into a mold. The steel is then hammered into the correct shape and excess steel is trimmed. The forged blade is then tempered by a sequence of heating and cooling of the steel in order to improve its durability and hardness. The blade is finally sharpened, fitted with a handle, and finished (which may involved polishing to remove any unwanted edges or burrs).
Stamped knives have their blades cut from large flattened sheets of steel. The steel may then be ground down to provide a taper from the spine to the edge as well has from the heel to the tip. Finally, the edge is sharpened, and the blade fitted with a handle. Both forged and stamped blades are made with a protrusion called the tang. The tang is where the handle will be attached through riveting, bonding, or another means.
In the past, forged steel was always deemed to be stronger and more durable than the steel used in stamped knives, but this is no longer necessarily true. The quality of steel used in some stamped knives can exceed the quality of steel in many forged knives. Also, stamped blades can be affixed with parts that are normally only present on forged knives such as a bolster or finger guard. As such, these features can no longer be used to determine accurately if a knife is forged or stamped -- but because a stamped blade is not necessarily a knife of poorer quality, one should not use the fact that a knife is stamped or not to determine if the knife is of higher or lower quality. Instead, the performance of the knife, how well balanced it is, feel, and finish should be much more important to the selection of the knife than whether or not the metal is stamped or forged.
Point - The point is the part of the knife at where the edge and the spine meet. The point is generally used for piercing.
Tip - The tip of the knife is usually considered the first third of the cutting edge including the point. This region is usually used for fine work or delicate cuts. The tip is also used as an anchor during mincing.
Edge - The cutting edge of the blade extends from the point to the heel. Virtually all cutting actions of the knife will use this region. Most cutting motions are performed by utilizing a slicing motion (drawing the knife horizontally while pressure is applied downward through force or gravity). In general, the main type of edges are taper ground edge (where the edge is formed by two straight bevels), hollow ground edge (where convex curves are carved out of the edge to form a sharper, thinner, more delicate edge), serrated edge (where the edge is shaped in a series of teeth), scalloped edge (where the edge is shaped in a series of small sharp arcs or bumps), or single edge (where only one side of the knife is beveled - like a chisel's edge). Some knives are labeled granton edge, but typically these knives have a taper ground edge and the blade has shallow divots cut out of it to reduce drag on the knife. These knives are also labeled scalloped, hollow ground, or dimpled by some vendors.
Heel - The heel is the part of the cutting edge farthest away from the point. Usually used when more weight and force are required to cut through (such as hard squashes or thin chicken bones).
Return - The return of the blade is the termination point of the heel. If the return is curved just right, then it allows a gentle rocking motion when preparing to make another stroke or slice with the knife. A well designed return can reduce fatigue and make repeated slicing a smooth cyclical motion instead of a staccato, paper cutter motion. If a finger guard is present on the knife, the return is often unable to be sharpened properly.
Spine - The spine is the top of the knife blade opposite of the cutting edge. A thick spine improves stability of the blade but may also make some cuts feel like you are driving a wedge instead of slicing with an efficient kitchen knife.
Bolster - The bolster is a collar that joins the blade of the knife to the handle. It's function is not to attach the blade to the handle, but to provide additional mass just forward of where the chef's hand is. This improves the stability, balance, and strength of the knife. Some bolsters are constructed with the blade (as in forged knives), while others are attached after the blade is constructed. In the past, it was easy to say that all such bolsters should be avoided because they were of poor quality, however many knife manufacturers have found ways of attaching bolsters to their blades with the same effectiveness as if they were constructed from the same piece of metal. Two notable examples of this are Zwilling J.A. Henckels (who manufacturers their forged blades with different metals for blade, bolster, and tang in a process they call Sintermetal Component Technology) and MAC Knife (who uses stamped steel for their blades). In general, knives which incorporate bolsters in their design are of higher quality than those which do not.
Bolster lip - The bolster lip is where the bolster tapers down to the blade. The lip can be steep, resulting in a sharp angle where the lip meets the blade or the lip can be gently sloped so it blends into the blade. Sharp angles can be a problem when washing the knife because small food particles may lodge in the corner and not be properly washed off. This may result in rusting, metal discoloration, or even bacterial growth if the material persists over time or water is trapped along with it. For this reason, preference should be given to knives with bolster lips that blend into the blade.
Finger guard - Often considered part of the bolster, the finger guard is designed to strengthen the heel of the knife, provide additional weight forward of the handle, and help a little to protect the finger from accidental slipping across the blade. The presence of the finger guard may make use of the heel easier by providing greater mass and stability, but at the same time may make it difficult to use the heel because it is physically larger and does not carry an edge. The use of the finger guard to strengthen the heel of the knife is generally unnecessary with modern steel formulations. A finger guard can be added to a stamped blade.
Tang - The tang is the part of the blade that actually extends into the handle of the knife. The handle is affixed to the blade through the tang. A full tang is a design where the tang is cut to the same size and shape as the handle and handle scales are affixed to both sides. Generally, a full tang is considered to be the most secure method of attaching a handle to a knife and is recommended for knives that will be seeing heavy duty action - like cleavers. Also common are encapsulated tangs which have handles molded onto a tang. Rat tail tangs are also enclosed within the handle and are generally affixed through the use of a bolt or pommel at the handle head. Half tang knives have a tang that only extends about halfway down the handle. These tangs are generally too short for knives that are used constantly or with a decent amount of force. Some half tang knives simply take the tangs and push them into the handle. These knives should be avoided. I recommend knives that have tangs of 3/4 length or full tang as these knifes will last the longest. The long tang gives the handle a better connection to the blade and whole knife will feel a little easier to control because of this connection and the extra weight it will provide to the back of the knife.
Scales - On knifes with riveted handles, the pieces of material (generally a type of wood) which are attached to the tang to form a handle are called the handle scales. The shape and material of the scales determines how the knife handle feels in the hand, if it will be comfortable after a long period or use, and whether or not it becomes slippery when wet or covered in fat. Scales should fit neatly behind the bolster and on both sides of the tang without slits or cracks (to ensure easy cleaning to avoid bacterial growth). The junction where the bolster and tang meet the scales should also be smooth (otherwise, the chef may develop blisters or rub their skin raw during use).
Rivets - Rivets are metal pins used to mechanically join the handle scales to the tang to form the handle. If the rivets are visible, they should be flush to the scales and no cracks should be present along the circle where the rivet meets the scale. Rivets are generally constructed with metal alloys that do not expand or contract much due to heat change to ensure a solid fit throughout the lifetime of the knife.
Handle guard - Many knives have a curvature that the end of the handle that is called a handle guard.
Butt or handle head - Butt is the terminal end of the handle of the knife. Handle head is another name for this part of the knife but is generally used when specifically discussing the handle of the knife.