Webster's New World Medical Dictionary

mother 1
The female parent. 
2
To produce off-
spring as a female. 
3
A cell or another structure
from which similar cells or structures are formed.
Such a cell might be referred to as the mother cell.
4
To provide maternal protection, guidance, and
nurturing to a child or children.
motility study, antro-duodenal
A study for
detecting and recording the contractions of the
muscles of the stomach and the first part of the
small intestine (the duodenum). An antro-duodenal
motility study is performed to diagnose problems in
the way the muscles of the stomach and small intes-
tine are working. To conduct the study, a tube is
passed through the nose, throat, esophagus, and
stomach until the tip of the tube lies in the small
intestine. The tube senses when the muscles of the
stomach and small intestine contract and squeeze
the tube tightly. The contractions are recorded for
analysis by a computer. Also known as antroduode-
nal manometry.
motion, range of
See 
range of motion.
motion sickness
A disorder of the sense of bal-
ance and equilibrium and, hence, the sense of spa-
tial orientation that is caused by repeated motion
such as from the swell of the sea, the movement of
a car, or the motion of a plane in turbulent air.
Motion sickness is due to irritation of a portion of
the inner ear called the labyrinth. The symptoms of
motion sickness include nausea, vomiting, and ver-
tigo. Other common signs of motion sickness are
sweating and a general feeling of discomfort and not
feeling well (malaise). Symptoms usually stop when
the motion that causes it ceases. However, some
people suffer symptoms for even a few days after the
trip is over.
motor
Something that produces or refers to
motion. For example, a motor neuron is a nerve cell
that conveys an impulse to a muscle for contraction,
which then moves a joint.