WordNet sense 1 (produced with the front of the tongue near or touching the hard palate (as `y') or with the blade of the tongue near the hard palate (as `ch' in `chin' or `j' in `gin')):

WordNet sense 2 ((of speech sounds); produced with the back of the tongue raised toward the hard palate; characterized by a hissing or hushing sound (as `s' and `sh')):