Refers to a special SSL certificate that secures multiple domain names with the same SSL certificate. Imagine if you own 5 domain names and you secure them with just 1 SSL Certificate. – that is SSL Certificate that can secure more than 1 domain name is called a multi-domain name SSL. For example, one SSL certificate that can secure Yourdomain.com, Yourdomain.net, Yourdomain.co.uk, Myotherdomain.com Note: Multi-domain name SSL Certificate come with 2 SAN by default – that is a new Multi-Domain SSL Certificate can secure up to 3 domain names. To secure additional domain names, you need to buy extra SANs. Sans are usually cheaper that a single domain name SSL and therefore it is economical to buy extra SANs for your Multi domain name SSL Certificate.