Raku loosely translates as enjoyment, contentment, pleasure and happiness
and these are meant to be embodied in the forms called Raku. Originally, these were utensils fore use in Japan's highly ritualized tea ceremony. Now, it is spread around the globe and comes to life in many functional and artistic embodiments
Wabi is a tough nut, particularly among westerners. It's to pottery what umami is to gastronomy: it emanates the natural world; has quiet, understated earthy elegance, it is a coming out or returning into nature but not in a harsh way; like the lotus it keeps you interested;
Sabi adds seeming history and age to wabi also incorporating serenity, melancholy, loneliness, and imperfection - a chip, a crack, an uninetended consequence of process - so that fresh from the fire the pot seems to have lived and maybe lived a very long time ago.
Wabi-sabi - Some commentators so closely identify sabi with wabi that they talk of wabi-sabi as a one concept.