Glossary
Montessori education has its own set of words. Schools, Instagram accounts, and sometimes people selling something, use these words a lot, often without explaining them. Here are plain definitions, linked to the pages on this site where each idea is explained more fully.
Disclosure: the author is the chair of the board of a Swedish Montessori school. You can read more in the conflict-of-interest disclosure.
Absorbent mind is Montessori’s term for how a child under six takes in their surroundings: language, movement, culture, emotional tone, almost all of it without trying, especially before age three. See Understanding the Stages.
AMI (Association Montessori Internationale): the organisation Maria Montessori herself founded in 1929, based in Amsterdam. It trains teachers and sets standards closely tied to her original lectures and materials. See Choosing a School.
AMS (American Montessori Society) is a US organisation founded in 1960. It also trains and accredits Montessori teachers, usually with more flexible training than AMI, and sometimes blends Montessori practice with mainstream school habits. See Choosing a School.
Auto-education: the idea that many Montessori materials are designed so a child can see their own mistake and fix it, without an adult stepping in to judge it. Closely related to control of error (below).
Casa dei Bambini (“Children’s House”): the name Montessori gave the first school where she developed her method, opened in Rome in 1907 in a tenement building. Many Montessori preschools still use this name today.
Control of error is a design feature built into a material itself. For example, a puzzle piece that only fits one way. It lets a child notice and fix a mistake on their own, rather than relying on an adult to correct them.
Cosmic education: the main idea of the 6–12 classroom. One connected story, running from the formation of the universe through the Earth, life and human history, used to tie every subject together instead of teaching them as separate blocks. See Understanding the Stages.
Erdkinder (“land children”) is Montessori’s own term, sketched only briefly, for a teenage (12–18) programme built around meaningful work on the land, in a community, rather than a normal timetable of lessons. It has been developed much further since by later practitioners, not by Montessori herself.
Going out: a planned trip outside the classroom, used from around age six onward, that lets children explore a question or a piece of research the classroom alone cannot answer.
Grace and courtesy: teaching social skills directly and on purpose (how to interrupt politely, how to offer help, how to greet someone), as its own part of the curriculum, rather than assuming children will pick up good manners on their own.
MACTE (Montessori Accreditation Council for Teacher Education) is the recognised US body that accredits Montessori teacher-training programmes across more than one organisation. Some schools and parents treat it as a baseline quality signal, separate from AMI or AMS branding.
NAMTA (North American Montessori Teachers’ Association), an AMI-linked organisation, is especially known for developing teenage (Erdkinder) programmes in North America.
Svenska Montessoriförbundet (the Swedish Montessori Association), founded in 1960, is Sweden’s own national Montessori body, an umbrella for more than 150 local Montessori associations. It runs NAMEX, Sweden’s own teacher-authorisation system, and publishes MontessoriTidningen. It is not a government body, and its authorisation is specific to Sweden, separate from AMI or AMS accreditation. See Choosing a School.
IMT (Institute of Montessori Training) is a Montessori teacher-training provider founded in the US in 2011, with its own lineage through Elizabeth Caspari, who trained directly under Maria Montessori, rather than through AMI. Its diplomas are MACTE-accredited. IMT launched a Swedish-language 3–6 programme in 2024, including a supervised residency week in Malmö. See Choosing a School.
Normalisation is a specific, technical Montessori term. It is not a comment on how a child starts out behaving. It means the shift, seen after sustained, purposeful, concentrated work, toward calmer, more self-directed, more cooperative behaviour. Montessori treated it as a predictable result of the environment and work routine functioning as intended, not as a personality trait a child either has or lacks.
Planes of development: Montessori’s framework of four roughly six-year stages (0–6, 6–12, 12–18 and 18–24), each with its own way of learning. See Understanding the Stages.
Practical life means real, purposeful, scaled-down versions of everyday tasks (pouring, dressing, preparing food), used especially with younger children, and different from toys that only imitate adult activity. See Montessori at Home.
Prepared environment is a space deliberately arranged so a child can act in it independently: ordered, within their reach, with a limited, curated range of options rather than everything available at once. See Montessori at Home.
Sensitive period means a temporary window of unusually strong, narrowly focused drive toward one kind of learning (language or movement, for example), which fades once that ability is in place.
Sensorial materials, used especially between ages three and six, isolate a single quality (size, colour, texture, weight, pitch), so a child can sharpen one kind of perception at a time.
Three-hour work cycle: a long, uninterrupted block of time in which children choose their own work and are not moved between activities on a fixed schedule. It is meant to let concentration build, rather than be reset by the clock.
For one free thing to try at home, Ten Quiet Minutes is a sheet you can print. It helps you watch what your child chooses, does again and leaves.
Correction, 11 October 2026: an earlier version of this page gave the four planes of development as 0–3, 3–6, 6–12 and 12–18. Montessori’s four planes are 0–6, 6–12, 12–18 and 18–24, as Understanding the Stages explains. The ages 0–3 and 3–6 are the two halves of the first plane. See the corrections log.
Sources consulted (paraphrased throughout; definitions are original summaries, not reproductions of any single glossary): Maria Montessori’s own works across her career (see the Historical Timeline for the full list and each publication’s copyright status); standard usage as reflected across AMI and AMS public materials; montessoriforbundet.se/om-oss and sv.wikipedia.org/wiki/ Svenska_Montessoriförbundet, for Svenska Montessoriförbundet; learn. aimmontessori.org/sweden-imt, for IMT. Simplified from the full-register version of this page; see that page for the complete, unsimplified account.