n.
Pronunciation: ' me-z ə - ˌ d ə rm, ' m ē -, -s ə -
Function: noun
Etymology: International Scientific Vocabulary
Date: 1873
: the middle of the three primary germ layers of an embryo that is the source of many bodily tissues and structures (as bone, muscle, connective tissue, and dermis) broadly : tissue derived from this germ layer
– me · so · der · mal \ ˌ me-z ə - ' d ə r-m ə l, ˌ m ē -, -s ə - \ adjective