[psy.chol.o.gy] n, pl -gies [NL psychologia, fr. psych- + -logia -logy] (1653) 1: the science of mind and behavior
2. a: the mental or behavioral characteristics of an individual or group b: the study of mind and behavior in relation to a particular field of knowledge or activity
3: a treatise on psychology -- psy.chol.o.gist n