Real Dictionary

Montessori method in American English
a system of training and teaching young children, devised in 1907 by Maria Montessori, which emphasizes training of the senses and guidance rather than rigid control of the child's activity, so as to encourage self-education
noun: a system for teaching young children, in which the fundamental aim is self-motivated education by the children themselves, as they are encouraged to move freely through individualized instruction and physical exercises, accompanied by special emphasis on

Montessori method in British English
noun: a method of nursery education in which children are provided with generous facilities for practical play and allowed to develop at their own pace