\Im*plo"sion\, n. [Formed by substitution of pref. im-
in for pref. ex- in explosion.]
1. A burstion inwards, as of a vessel from which the air has
   been exhausted; -- contrasted with explosion.
2. (Phon.) A sudden compression of the air in the mouth,
   simultaneously with and affecting the sound made by the
   closure of the organs in uttering p, t, or k, at the end
   of a syllable (see Guide to Pronunciation,
   [sect][sect]159, 189); also, a similar compression made by
   an upward thrust of the larynx without any accompanying
   explosive action, as in the peculiar sound of b, d, and g,
   heard in Southern Germany. --H. Sweet.