What is SSL (Secured Sockets Layer)?
SSL is an acronym for Secure Sockets Layer, a global standard security technology adopted by Netscape in 1994. SSL is designed to establish encryption and identity assurance. It creates an encrypted link between a web server and a web browser. The link ensures that all data passed between the web server and browser remains private and secure. Raise your guards against the data getting hacked.
How SSL works
Processing transactions securely on the web means that we need to be able to transmit information between the web site and the customer in a manner that makes it difficult or not worthy for other people to intercept and read. SSL works through a combination of programs and encryption/decryption routines that exist on the web server computer and in web browsers (like Netscape/Firefox and Internet Explorer) used by the Internet public
What is an SSL Certificate?
SSL certificates becomes the "passport" or the digital document that verify that the security and authenticity of the interaction.Save 20% on Premium Website Security SSL at GoDaddy.com
The SSL certificate is installed on a web server to identify the business using it to encrypt sensitive data such as credit card information. SSL Certificates give a website the ability to communicate securely with its web customers. Without a certificate, any information sent from a user’s computer to a website can be intercepted and viewed by hackers and fraudsters. It is similar to the difference between sending a post card and a tamper proof sealed envelope.
Source of the text above - http://www.evsslcertificate.com/ssl/description-ssl.html
If you want to know how SSL Works, here it is: