A chicken paillard is just a fancy French way of describing pounded chicken cutlets. As a technique for home cooks, it's one of the most useful; Once you know how to do it, a hot chicken dinner is only a few minutes away. When pounded to a quarter inch, chicken breast takes about four minutes total to cook in a hot skillet.
'paillard' on Serious Eats
I'm no culinary blowhard—half the time I can't retain the fancy-pants French cooking terms anyway. But I am big fan of paillard. For such an ostentatious term, one that seems like it should describe a ballet move or a European building, paillard is one of the least complex and most approachable food preparations I've learned.