H/T Grantland

The speed rating of a tire is based on U.S. Government standards for reaching and sustaining a specified speed. Typically, a tire with a higher speed rating results in better handling. Speed ratings apply only to the tire itself, and not to a particular vehicle. Putting a tire rated for a certain speed on a vehicle does not mean that the vehicle can be safely operated at the tire's rated speed.

A tire’s maximum load is the maximum amount of weight the tire is designed to hold. The tire’s load carrying capacity is directly related to the tire’s size and amount of inflation pressure that is actually used. Each load range has a assigned air pressure identified in pounds per square inch (psi) at which the tire's maximum load is rated.

This is how much weight a tire is rated to hold.

Tire Load Range refers to the maximum weight a tire can safely support at a specified tire pressure. For Light Trucks and SUVs, ranges are usually expressed using SL (Standard Load) and XL (Extra Load or Reinforced). It can also be represented by letters (e.g., C, D, E), which indicate the tire's ply rating, which traditionally referred to the number of layers of material within the tire.

A higher load range indicates a tire designed to carry heavier loads. For example, a tire with a Load Range E can support more weight than one with a Load Range C. The correct load range is critical for vehicle safety and performance, especially for trucks, trailers, and commercial vehicles.

Tread depth is the distance between the top of the tread rubber to the bottom of the tire's deepest grooves.  In the United States, tread depth is measured in 32nds of an inch.

The measurement, in inches, from rim flange to the other rim flange. 

This is how many layers of rubber and other materials are in the tire.  

This number will tell you how well the tire will disperse heat buildup. 

A tire’s maximum inflation pressure (PSI) is the highest "cold" inflation pressure that the tire is designed to contain. When measuring a tire’s max PSI, it is important the tire is "cold," because warmer temperatures can cause the tire pressure to temporarily increase resulting with inaccurate readings. This measurement should only be used when called for on the vehicle’s tire placard or in the vehicle’s owners manual.

A tire's section width (also called "cross section width") is the measurement of the tire's width from its inner sidewall to its outer sidewall (excluding any protective ribs, decorations or raised letters) at the widest point. 

The mileage warranty of a tire indicates the number of miles that a tire is estimated to last. If a tire fails to last for the number of miles indicated by the warranty, the customer will be given credit from the tire manufacturer toward a new tire based on how many miles short of the estimate the tire fell. Some restrictions apply.