Wordnet 3.0
NOUN (2)
1.
a muscle that contracts without conscious control and found in walls of internal organs such as stomach and intestine and bladder and blood vessels (excluding the heart);
[syn: smooth muscle, involuntary muscle]
2. muscle tissue that does not appear striated under the microscope; has the form of thin layers or sheets;
WordNet (r) 3.0 (2006):
smooth muscle
n 1: a muscle that contracts without conscious control and found
in walls of internal organs such as stomach and intestine
and bladder and blood vessels (excluding the heart) [syn:
smooth muscle, involuntary muscle]
2: muscle tissue that does not appear striated under the
microscope; has the form of thin layers or sheets