Some part of the articulating organs, as the lips, or the
   tongue and palate, closed (a) so as to cut off the passage of breath or
   voice through the mouth and the nose (distinguished as a lip-stop, or a
   front-stop, etc., as in p, t, d, etc.), or (b) so as to obstruct, but
   not entirely cut off, the passage, as in l, n, etc.; also, any of the
   consonants so formed.