Webster's New World Medical Dictionary

aortitis
Inflammation of the aorta. The causes of
aortitis include syphilis and rheumatic fever.
AP 1
Angina pectoris.
2
Arterial pressure.
3
In endocrinology, anterior pituitary gland.
4
In
anatomy, anteroposterior.
aperient
Laxative.
Apert syndrome
The best-known type of acro-
cephalosyndactyly, a group of disorders character-
ized by malformations of the skull, face, hands, and
feet. Apert syndrome is inherited as an autosomal
dominant trait. See also 
acrocephalosyndactyly;
fibroblast growth factor receptor.
apex
The Latin word for summit, the apex is the
tip of a pyramidal or rounded structure, such as the
lung or the heart. The apex of the lung is indeed its
tip—its rounded most superior portion. The apex
of the heart is likewise its tip, but it is formed by the
left ventricle, so it is essentially the most inferior
portion of the heart.
Apgar score
An objective score of the condition
of a baby after birth. This score is determined by
scoring the heart rate, respiratory effort, muscle
tone, skin color, and response to a catheter in the
nostril. Each of these objective signs receives 0, 1,
or 2 points. An Apgar score of 10 means an infant
is in the best possible condition. The Apgar score is
done routinely 60 seconds after the birth of the
infant. A child with a score of 0 to 3 needs imme-
diate resuscitation. The Apgar score is often
repeated 5 minutes after birth, and in the event of a
difficult resuscitation, the Apgar score may be done
again at 10, 15, and 20 minutes.
aphagia
Inability to eat.
aphasia
Literally, no speech. Aphasia may also be
used to describe defects in spoken expression or
comprehension of speech.
apheresis
The process of removing a specific
component from blood temporarily. Also known as
hemapheresis and pheresis. Forms of apheresis
include plasmapheresis, harvesting plasma or liquid