As you dip your toe into the Twittosphere, here is a list of must-know Twitter terms to help you decipher the platform and messaging. Some of these may seem obvious or highly simplistic, but a legend may help dispel some of the mystery or myth behind it.

Handle

Your Twitter username. They all begin with @. For example, my Twitter handle is @innovatebyday. If you include another user’s @handle in your Tweet, it will go into that user’s feed, whether they specifically follow you or not.

Tweet

The messages posted publicly on Twitter are called Tweets. Tweets are limited to 140 characters in length, so craft your Tweets carefully.

DM (Direct Message)

This is a private message that only the sender and recipient can view.

# (Hashtag)

The symbol commonly used to identify the specific topic of a Tweet, so that people searching out the topic can find it more readily. Searching for #Oscars or #SuperBowl will help you find what people are saying about the topic; and help others interested in the topic find YOU. Who started all this #hashtag stuff, anyway? We’re glad you asked. Credit goes to Chris Messina (not the actor). Read about the origins of the hashtag here: http://gigaom.com/2010/04/30/the-short-and-illustrious-history-of-twitter-hashtags/ And for other very smart conventions Chris Messina has tried to get started (with limited success): http://factoryjoe.com/blog/2009/11/08/slashtags/

#FF (Follow Friday)

This hashtag, used by countless Twitter users every Friday, identifies a list of notable accounts to follow. This is a great way to find interesting new people to follow. And when you follow a user, there’s a pretty good chance that s/he will follow you back. You may want to tweet your own #FF lists.

RT (Re-Tweet)

The text following the RT was Tweeted by one user and resent (Re-Tweeted) in its full form by another. By clicking ReTweet, you share the complete Tweet with your followers; by using RT in the body of your Tweet, you can share your thoughts as well as the quoted Tweet.

PRT (Partial Re-Tweet)

Acknowledges the original user’s message and main point or point that resonated

MT (Modified Tweet)

Indicates that the message was modified or altered slightly from the original Tweet

HT (Hat Tip or Heard Through)

This is a way to attribute a link to another user without copying the text of the original Tweet.

CC (Carbon Copy)

As with e-mail or (gasp) letters.

Link

Generally means it includes a URL in your Twitter message.

Trending

The current most-talked-about subjects or #Hashtags on Twitter are said to be “Trending”. (The geography around “trending” topics is broken out by Twitter).

Twittosphere, Twittersphere or Twitterverse

The world of Twitter. The social space created by Twitter, where millions of us are talking about everything and nothing, in 140 characters or less. *** This is by no means comprehensive — please use the Comments section to let us know if there’s anything you feel we’ve left out. Upcoming: Innovate by Day’s handy downloadable Twitter abbreviations cheat sheet!