A Target television ad asks at the beginning “When is a door not a door?” Later in the ad comes the answer: “when it’s a portal.”
So what’s the difference?
A door is an opening through which one may pass through a wall. So is a portal, but a portal leads to something special. In the ad, the portal is seen to be an opening that leads people to better, more fulfilling lives.
Most words have connotations that subtly affect the emotions of a reader. Sensitive writers will weigh such connotations in their final revisions.
Here are some other words whose denotation, like that of door, is “opening or passage through an obstacle,” and some notes on their possible connotations.
door – a movable structure used to close off an entrance, typically consisting of a panel that swings on hinges or that slides or rotates. Generic term
doorway – opening to a room, building, or passage – it may or may not have a hinged door installed. For example, a character might be in an unfinished house or a ruined house with “empty doorways.”
portal – a doorway, entrance, or gate, especially one that is large and imposing.
passageway – an extended entrance, like a corridor. The word could be used to imply initiation.
entrance – a means or point by which to enter. Generic term.
entry – a means or place by which to enter. Possibly fancier than an entrance
entry-way – a passage or opening by which to enter. Like doorway, an entry-way may or may not have a door attached.
opening – an open space serving as a passage or gap. The opening to a cave, the opening to another dimension.
gate – a structure that can be swung, drawn, or lowered to block an entrance or a passageway. A gate is usually out-of-doors, but not always.
exit – a way out