Running Dictionary

Some running terms and their definitions, courtesy of Wikipedia:

Tempo runs
Speed for long distance running can be improved using a number of training strategies, with tempo runs considered the best by most trainers at this time. A tempo run consists of a warm up phase, a tempo pace phase, and a cool down phase. Typically the warm up and cool down phases may cover one or two miles (3 km), while the tempo pace phase may be two to six miles (or 20 to 35 minutes), depending on the individual and the goals.

Tempo pace is usually run at what is called the individual's lactate threshold which has been determined in laboratory and other tests to be the optimal metabolic rate at which an individual can train. At this pace, the body is removing lactic acid as fast as it is being produced, any faster and lactic acid will build up in the individual's system, any slower and optimal training does not result.
Every individual has a different lactate threshold pace, which increases over time as that individual trains more and more.

Long Runs
The long run is the heart of the marathon training process. The goal of the long run is to gradually increase the ability of the runner to cover the 42.195 kilometres (26.219 mi) marathon distance. Long runs may start at 6 miles (9.7 km), and build a mile a week to about 14 or 15 miles (24 km). At beyond 15 miles (approximately), more than a single week of recovery is generally necessary, so the schedule switches to a two-week plan, with a shorter "long run" between full long runs.

Pace during long runs should be conversational, meaning that one should be able to carry on a conversation; it is not necessary to run at top speed. Long runs at less than top speed (60 to 70% of maximum exertion level) train the body to store energy more efficiently and make more effective use of oxygen.

Speed Work (my definition)
Similar to tempo runs, with warm-up and cool-down periods. The intervals are shorter but faster, with recovery periods in between.