Is a surname?
If you have only one name, just make this clear as you fill our your paperwork. I've seen people with only 1 name on a US visa. If you have an error on your current passport or birth certificate, though, you need to correct it before beginning the visa process. Make sure all of your documents have the same version of your name, or it could cause you some problems when you apply for US Immigration benefits or travel in/out of the US.