PRT has 2 meanings
When a tweet includes PRT, it might be a "partial retweet." The user who posted this tweet took it from another user, but removed part of the message before reposting it.
Typically, PRTs are condensed to highlight the most pertinent part of the original tweet. Shortening a retweet in this way also allows the retweeter to add their own commentary.
For example, you might see a tweet that reads "Can't believe it. PRT: @AppleNerd Apple to Buy Spotify." The original version of @AppleNerd's tweet likely included more information about the purchase.
PRT @WeatherGal The hurricane ... was a category 5.
|Retweet offender||A person who constantly retweets on Twitter|
A Twitter acronym used to politely ask for a retweet; commonly utilized by a Twitter user looking to get a tweet seen by more than just his or her followers.