A magician might preordain the sudden appearance of a rabbit from an empty hat — in other words, she predicts or decides that she'll magically produce the rabbit. Other things preordain certain results by simply pointing in that direction or making the outcome seem inevitable. Torrential rain preordains a soggy croquet course the next day, and a plane's flight plan preordains exactly where (and approximately when) it will land. Pre- means "before," and ordain means "decide" or "order."