Aluminum -  Very light, malleable, and ductile with high heat and electrical conductivity.  Non-magnetic with good corrosion resistance against certain chemicals and acids but weak resistance against other elements such as sea water.

Belleville Washer-   Domed, compression washer

Bevel Washer-  Slanted, square washer which is thicker on one side than the other.  The slant of the bevelled washer can offset a slanted surface, so that a bolt going into the washer may be parallel to the floor or ground.

Brass -   About two-thirds copper, one-third zinc.  Non-magnetic with good strength, toughness and high electrical conductivity.  Good corrosion resistance, but not in salt water. 

Chromium- The most important element providing corrosion resistance in stainless steel.   BY adding 12% chromium to ordinary steel, stainless steel is formed.  Chromium offsets the corrosive effects of carbon found in steel and is the primary factor in the ability of stainless to form a passive film on its surface providing corrosion resistance.

Copper - Excellent conductor of heat and electricity.  It is malleable, ductile, and non-magnetic with low to average strength and good corrosion resistance.

Fender washer - An over sized flat washer with a larger outside diameter used to further distribute load, especially on soft materials.

MS - Stands for Military Standards.  The overriding characteristic of MS fasteners compared to commercial products is the extensive inspection and lot traceability for MS.

Monel- Composed basically of two-thirds nickel, one-third copper with good strength, excellent corrosion resistance against salt water and in high temperatures.

Non-Ferrous - Metals without iron, such as brass and silicon bronze.

Nylon- Light and low in strength compared to metal fasteners.  Nylon is non-magnetic, good for insulation, and corrosion resistant against many chemicals.

SAE- Stands for Society of Automotive Engineers

SILICON BRONZE- Alloy made of 95% - 98% copper, plus a small amount of silicon for added strength.  Small amounts of manganese and aluminum may also be added for strength, and lead may be added for machineability.  Silicon bronze is non-magnetic, with a high degree of thermal conductivity and high corrosion resistance against sea water,gases, and sewage.

STAINLESS STEEL-  With the addition of 12% chromium to iron, stainless steel is formed.  The chromium protects the iron against most corrosion or red-colored rust.
More detailed stainless steel information can be found here.

TAP BOLT- Fully threaded hex bolt that would normally have partial threading.