What does RT mean on Twitter?

[Laura,x]

if i were to tweet something and you liked it you could RT, and this means retweet, by doing this you are almost sharing the tweet with your followers, it'll come up on your page that you've done so and the tweet will still say that it was by the original person, ie, me.

http://nonprofitorgs.files.wordpress.com...=600&h=350

If you look at this picture, some of this person's tweets have a green half arrow thing in the corner, this means that they have retweeted that person's tweet, so they never wrote it but are almost "sharing" it, if you have facebook for example, its like someone sharing your photo.