I used openssl to create a X.509 certificate but I don't quite understand the relationship between a X.509 and a SSL certificate. Are they the same? Is a SSL certificate just a X.509 certificate that is used for SSL?
SSL is by far the largest use of X.509 certificates, many people use the terms interchangeably. They're not the same however; a "SSL Certificate" is a X.509 Certificate with Extended Key Usage: Server Authentication (1.3.6.1.5.5.7.3.1).

Other "common" types of X.509 certs are Client Authentication (1.3.6.1.5.5.7.3.2), Code Signing (1.3.6.1.5.5.7.3.3), and a handful of others are used for various encryption and authentication schemes.
