1) Abnormal 2) Below normal or average 3) Below the normal 1) Abnormal 
• (n.) That part of the axis of a curved line which is intercepted between the ordinate and the normal.
(sәb-nor´mәl) below or less than normal.
Sub·nor'mal noun (Geom.) That part of the axis of a curved line which is intercepted between the ordinate and the normal. 
Type: Term Pronunciation: sŭb-nōr′măl Definitions: 1. Below the normal standard of some quality.
[adj] - (statistics) below normal or average 2. [n] - a person of less than normal intelligence
adjective below normal or average; `after the floods the harvests were subnormal`; `subnormal intelligence`
below the normal; less than or inferior to the normal: a subnormal amount of rain. · being less than average in any psychological trait, as intelligence, personality, or emotional adjustment.