1.  depressor(n = noun.body) depressor muscle - any skeletal muscle that draws a body part down;
is a kind of skeletal muscle, striated muscle
Derived form verb depress₃

2.  depressor(n = noun.body) depressor nerve - any nerve whose activity tends to reduce the activity or tone of the body part it serves;
is a kind of nerve, nervus

3.  depressor(n = noun.artifact) - a device used by physician to press a part down or aside;
is a kind of device
has particulars: tongue depressor
Derived form verb depress₄

depressor, n.
1 Anat. a (in full depressor muscle) a muscle that causes the lowering of some part of the body. b a nerve that lowers blood pressure.
2 Surgery an instrument for pressing down an organ etc.

Etymology:
L (as DEPRESSION)

depressor muscle, depressor nerve, tongue depressor