#sand
Top Voted Definition for #sand
The hashtag (#) is also known in American English as the pound sign, referring to the unit weight. Thus, #sand, could be read as "pound sand," and telling someone to "go pound sand" is equivalent to telling someone to "get lost," or "go fly a kite." Use #sand in tweets to tell someone to "go pound sand." Read more... http://www.urbandictionary.com/define.php?term=pound%20sand
2