Definition of portal

• n. - A door or gate; hence, a way of entrance or exit, especially one that is grand and imposing.
• n. - The lesser gate, where there are two of different dimensions.
• n. - Formerly, a small square corner in a room separated from the rest of the apartment by wainscoting, forming a short passage to another apartment.
• n. - By analogy with the French portail, used by recent writers for the whole architectural composition which surrounds and includes the doorways and porches of a church.
• n. - The space, at one end, between opposite trusses when these are terminated by inclined braces.
• n. - A prayer book or breviary; a portass.
• a. - Of or pertaining to a porta, especially the porta of the liver; as, the portal vein, which enters the liver at the porta, and divides into capillaries after the manner of an artery.