Échappé means to escape OR to no longer be held back/restrained.  Both variations of the definition fit the movement perfectly and the variation can even be helpful in distinguishing between échappé sauté and échappé sur les pointes. 

Échappé is pronounced [eʃape].  É sounds like the pronunciation of the letter A (be sure not to include a y sound on the end), ch sounds like shhh, a sounds like a soft open A sound, ppé sounds like pay (without the final y).

Échappé whether performed as a sauté or sur les pointes is a movement beginning in a closed, crossed position such as 5th or 3rd position, opening to fourth or second position, and returning to a closed, crossed position.

Échappé sauté fits perfectly with the simple definition "to escape."  The feet jump apart and then back together.  Your littlest dancers will love the idea that the feet escape their 5th position to land in second and then get "caught" again back in 5th, and your older dancers will hold on to this image as a way to retain the vocabulary.  Imagine that each foot is a friend who got caught being naughty, both friends run in different directions, but both get caught again.  The movement is quick and and exciting.  This movement can also be performed with the feet jumping to fourth.

I love to relate échappé sur les pointes to the second variation of the definition.  The dancer performs a plié in the closed position, releases the feet that then slide apart to second or fourth, and then, with control, pulls the two escapees back in to the closed position.  The idea that the dancer is holding the feet back in fifth and allowing them to slide apart to the open position creates a better action for pointe work and helps avoid the pounce that often happens with dancers new to pointe.