No a DOS attack is much different. I had this happen to a place that I was hosted through once. Here goes the definition for those who don't know:
DoS attack
Short for denial-of-service attack, a type of attack on a network that is designed to bring the network to its knees by flooding it with useless traffic. Many DoS attacks, such as the Ping of Death and Teardrop attacks, exploit limitations in the TCP/IP protocols. For all known DoS attacks, there are software fixes that system administrators can install to limit the damage caused by the attacks. But, like viruses, new DoS attacks are constantly being dreamed up by hackers.
A lot of times because they are going directly at the server, an attack such at this will drop many sites. Most often, they are not directed at an individual for any reason other than pure enjoyment. Sometimes they will however do this to a specific person on purpose. This type of attack also can be caused by a website that's got something formatted improperly, like a php or asp script that run at server level. This latter was the case with the server I was on.