ˈmidlə(r) noun
( -s )
Etymology: middle (I) + -er
1. obsolete : interagent , mediator
2. : one belonging to an intermediate group, division, or class: as
a. : a student in the second year class of a theological seminary having a three-year program
b. : a student in the second or third year class in some private secondary schools having a four-year course
c. : a student in a division in some private schools that corresponds approximately to the junior high school — compare middle school
3. : a rolling-mill operator tending the middle set of rolls — called also plateman