look up any word, like the eiffel tower:
 
1.
A unit of measurement equalling "billions and billions"


From Carl Sagan, well-known astronomer and popular science author
On a clear night, you can see a whole sagan of stars.

Don't drink the water - there's a sagan of germs swimming around in there!
by Serai April 05, 2004
 
2.
scientifically exciting, wonderment
Working to uncover the mysteries of the universe is such a sagan!
by Cari Greene August 22, 2003
 
3.
An intelligent person who is not only well-versed in his/her subject, but is also graced with an ability to make that subject come to life for others who may not have as much knowledge. A Sagan knows how to evoke childlike wonder and awe, while not taking himself/herself too seriously. Humanisitic, warmhearted, optimistic, and unpretentious. Not just a sage - a Sagan.
"That Neil DeGrasse Tyson - what an excellent example of a Sagan!"

"Yeah, David Suzuki too!"
by smendler May 21, 2013
 
4.
Some guy on the net that has enough DOS bots and exploit knowledge to drop the net.
I have a death wish so i'm going to go into Sagan's IrCQNet channel and abuse him.
by Urban Dictionary October 17, 2003
 
5.
some dude on the net that fucked me up :(
i got fucked up
by smithay December 11, 2003