Dictionary.net

• Of or pertaining to the monitorial system of instruction followed by Joseph Lancaster, of England, in which advanced pupils in a school teach pupils below them.

2010 - New Age Dictionary Database
By Oddity Software

• Of or pertaining to the monitorial system of instruction followed by Joseph Lancaster, of England, in which advanced pupils in a school teach pupils below them.

1913 - Webster's Revised Unabridged Dictionary
By Noah Webster.