an imposing entrance to something, such as a large/grand door or gate, approach to a bridge, or mouth of a tunnel;
e.g. The huge gates were a portal to the magical world beyond them.
(noun)
a website that enables access to other websites, often featuring a search function and then providing links to other sites, usually arranged according to some system;
e.g. You can use this portal to view the various job opportunities available.
(adjective)
relating to an area of an organ where a major blood vessel passes through, especially relating to the specific section of the liver where several blood vessels enter the organ;
e.g. The doctor suspected a portal blockage, and ordered scans to check for this.