This terms refers to the length of time that a website has been active. Domain age is a factor when it comes to SEO, as search engines place more trust on websites that are older, as it makes them more established.
Sean Si is a Filipino motivational speaker and a Leadership Speaker in the Philippines. He is the head honcho and editor-in-chief of SEO Hacker. He does SEO Services for companies in the Philippines and Abroad. Connect with him at Facebook, LinkedIn or Twitter. Check out his new project, Aquascape Philippines