To annoyingly "tag" objects, emotions or feelings by adding a "#" (hashmark) and then the thing wanting to be said.
1. "OMG. So excited for PLL tonight! Gonna enjoy it with @Stupid GirlyFace!!! #happy!"

2. "No one will talk to me. #depressed"

3. "UGH! SO pissed! I guess I'll just #hashtag #hashtag #hashtaggetytagatg!"

.
.
.

4. Something only accepted on twitter. Not on Facebook or the like.
by maybemaddening July 27, 2011
what people say to people who are noobs to the internet
1: wtf is that noughts and crosses thing on my keyboard????
2: it is a #hashtag u n00b.
by McTreevil February 21, 2015
twitter vocab.
if you understand the concept of hashtags, you'll understand "#hashtag."
it's basically a wild card for hashtags and leaves it open for interpretation for the reader.
it can even fill a void when no words can properly describe the extreme extent of the tweet (situation) perfectly. or use when you're having a hard time coming up with a clever hashtag.
when you can relate to the situation and/or picture it happening.

basically if you ever catch yourself saying "i dont know what to hashtag" use #hashtag
sample tweet: when you catch someone checkin someone out... #hashtag #iknowyoudontknowthatiknow

sample tweet: lost my phone at the bar last night #drunkgirlproblems #hashtag #pissedaf

sample tweet: my roommates feet smelled up our entire room #hashtag

sample tweet: just got pulled over #hashtag
by hashtagqueen March 2, 2012
Overused word used by hipsters to add tags to everything they do.
Guy: Hey, sup?
Crush: OMG. Hashtag chillin'. Hashtag Friday. Hashtag Shopping. Hash-
Guy: O.K. I' done here.
by French Swan April 7, 2015
Let's not even set an example for this annoying fad #hashtag #stupid
by Shitbrick1502 June 13, 2013
If you have been on Twitter, you may have seen a "hashtag." To put it simply, a hash tag is simply a way for people to search for tweets that have a common topic and to begin a conversation. For example, if you search on #LOST (or #Lost or #lost, because it's not case-sensitive), you'll get a list of tweets related to the TV show. What you won't get are tweets that say "I lost my wallet yesterday" because "lost" isn't preceded by the hash tag.

Hashtags believed to have originated on Twitter but, interestingly enough, it is not a Twitter function. Some believe it began when the broken plane luckily landed in the Hudson River in early 2009, some Twitter user wrote a post and added #flight1549 to it. I have no idea who this person was, but somebody else would have read it and when he posted something about the incident, added #flight1549 to HIS tweet. For something like this, where tweets would have been flying fast and furiously, it wouldn't have taken long for this hash tag to go viral and suddenly thousands of people posting about it would have added it to their tweets as well. Then, if you wanted info on the situation, you could do a search on "#flight1549" and see everything that people had written about it.
Take this ashtag for example: #worstjobeverhad. This Hash tag would compel many others to share the worst jobs they've ever had, thus contributing to a fun conversation. It can be used for specific searches or individual twitters that begin them for their followers.

For further clarification on hashtags and for everything for everything else Twitter please visit: TwitterFanZone.com
by itweet November 13, 2010
A hashtag is a stupid thing people put in front of random words for no reason. It is just the pound sign you can find it on social networks like Facebook or Twitter. It is just another 21st century made up thing.
A hashtag is,
#Beautiful
#Urbandictionary
by Hanna Forman July 5, 2013