Weather Watcher Live is able to display weather data from three sources: WeatherBug, Weather Underground, NWS. Each source decides how they are going to label weather conditions and weather events. We could collect that content and store it in a single place, but that would consume untold man hours and would take a lot of time to maintain. It would be best to visit the source directly to find those answers.
The weather terms that I see are usually pretty straightforward (e.g. "cloudy" v.s. "party cloudy"). I find that the severe alert titles aren't as straightforward (e.g. "Thunderstorm Warning" v.s. "Thunderstorm Watch"), but the descriptions do a good job of explaining. The glossary at WeatherBug.com does a good job of explaining those differences:http://weather.weatherbug.com/weather-glossary/weather-glossary.html