Selective serotonin reuptake inhibitor. Selective serotonin reuptake inhibitors (SSRIs), also known as serotonin-specific reuptake inhibitors or serotonergic antidepressants,[1] are a class of drugs that are typically used as antidepressants in the treatment of major depressive disorder and anxiety disorders.
Then you're looking for the midpoint! The midpoint of a line segment is the point located midway between the endpoints of the line segment. This tutorial tells you about the midpoint of a line segment.
There is another less popular measure of center called the midrange. which is actually the midpoint of the range. The midrange is not widely used since it is dependent upon only two values in the set. The mean of a distribution can also be thought of as a balance point for the distribution.