Meaning - The temporary acceptance as believable of events or characters that would ordinarily be seen as incredible. This is usually to allow an audience to appreciate works of literature or drama that are exploring unusual ideas.
Origin - This term was coined by Samuel Taylor Coleridge in 1817 with the publication of his Biographia literaria or biographical sketches of my literary life and opinions:
"In this idea originated the plan of the 'Lyrical Ballads'; in which it was agreed, that my endeavours should be directed to persons and characters supernatural, or at least romantic, yet so as to transfer from our inward nature a human interest and a semblance of truth sufficient to procure for these shadows of imagination that willing suspension of disbelief for the moment, which constitutes poetic faith."
The state is arguably an essential element when experiencing any drama or work of fiction. We may know very well that we are watching an actor or looking at marks on paper, but we wilfully accept them as real in order to fully experience what the artist is attempting to convey.
Most young children are able to separate the literal from what is pretend. But some cannot. Be careful in directing young actors and be mindful that some children have trouble understanding directions in "make-believe." You may have to do preparatory exercises to help them learn the difference between real and make-believe. Using costumes and props are important tools to help them separate the times when they are acting from the times when they are not.
When young children learn to use their imaginations and suspend their disbelief, their enjoyment of stories can be so profound. Fictional stories can be useful to help them learn lessons for the real world. Trouble and strife and untold bad things can be experienced in "make-believe" without all the real-life consequences. What a wonderful gift to be able to learn through thought-provoking stories just by suspending our disbelief for a little while.