— isotonicity /uy'seuh teuh nis"i tee/ , n.
/uy'seuh ton"ik/ , adj.
1. Also, isosmotic . Physical Chem. noting or pertaining to solutions characterized by equal osmotic pressure. Cf. hypertonic (def. 2), hypotonic (def. 2).
2. Physiol.
a. noting or pertaining to a solution containing the same salt concentration as mammalian blood.
b. noting or pertaining to a muscular contraction in which constant tension continues while the length of the muscle decreases, as during mechanical work.
3. Music. of or characterized by equal tones.
[ 1820-30; isóton ( os ) having equal accent or tone (see ISO-, TONE) + -IC ]