It may be serious or casual, straight or gay, committed or open, short-term or long-term.
To me, dating means a couple have started seeing each other, spending time together, but not yet far enough along to be in an ecvlusive relationship.
In other words, you only met recently and are still getting to know each other.
It doesn't mean you can't go on dates with other people. That comes later, IF the 2 people are compatible and choose to move to the next level.