Glossary
Montessori education has its own vocabulary, and a lot of it gets thrown around by schools, by Instagram accounts, and occasionally by people selling something, with little explanation. These are plain-language definitions, cross-referenced to the pages on this site where each idea is explored more fully.
Disclosure: the author chairs the board of a Swedish Montessori school. See the conflict-of-interest disclosure.
Absorbent mind is Montessori’s term for the way a child under six takes in their environment: language, movement, culture, emotional tone, almost all of it without conscious effort, especially before age three. See Understanding the Stages.
AMI (Association Montessori Internationale): the organisation Maria Montessori herself founded in 1929, based in Amsterdam, which 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 that also trains and accredits Montessori teachers, generally with more flexible training structures than AMI, and sometimes blends Montessori practice with mainstream school conventions. See Choosing a School.
Auto-education: the idea that many Montessori materials are designed so a child can see their own mistake and correct it without an adult stepping in to judge or mark 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 housing block, and still the name many Montessori preschools use today.
Control of error, a design feature built into a material itself (for example, a puzzle piece that only fits one way), lets a child notice and fix a mistake independently rather than relying on an adult’s correction.
Cosmic education: the organising idea of the 6–12 classroom, a single connected story that runs 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 an adolescent (12–18) programme built around meaningful work on the land in a community setting rather than a conventional timetable of lessons. It has been largely extended and developed since by later practitioners, not by Montessori herself.
Going out, a structured excursion outside the classroom used from around age six onward, lets children pursue a question or a piece of research that the classroom alone can’t answer.
Grace and courtesy: the explicit, practised teaching of social conventions (how to interrupt politely, how to offer help, how to greet someone) as its own area of the curriculum, rather than an assumption that children will absorb manners by osmosis.
MACTE (Montessori Accreditation Council for Teacher Education) is the recognised US body that accredits Montessori teacher-training programmes across more than one affiliated organisation. Some schools and parents treat it as a baseline quality signal independent of AMI/AMS branding.
NAMTA (North American Montessori Teachers’ Association), an AMI-linked organisation, is particularly associated with developing and extending adolescent (Erdkinder) programming in North America.
Svenska Montessoriförbundet (the Swedish Montessori Association), founded in 1960, is Sweden’s national Montessori membership body, an umbrella organisation for more than 150 local Montessori associations. It administers NAMEX, Sweden’s own teacher-authorisation examination, and publishes MontessoriTidningen. It is a membership and advocacy organisation, not a government authority, and its authorisation is distinct from, and not equivalent in scope to, AMI or AMS accreditation internationally. See Choosing a School.
IMT (Institute of Montessori Training), founded in the United States in 2011 by Mary Ellen Maunz, traces its training lineage through Elizabeth Caspari, who trained directly under Maria Montessori, rather than through AMI; the two organisations are unrelated despite the similarity some associate with the name. Its diplomas are MACTE-accredited. In September 2024 it launched a Swedish-language 3–6 programme, including a supervised residency week in Malmö. See Choosing a School.
Normalisation is a specific, technical Montessori term, not a comment on any child’s starting behaviour: the observed shift, after sustained access to purposeful, concentrated work, toward calmer, more self-directed, more socially cooperative behaviour. Montessori treated it as a predictable result of the environment and work cycle 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 a distinct mode of learning. See Understanding the Stages.
Practical life means real, purposeful, scaled-down versions of everyday tasks (pouring, dressing, food preparation), used especially with younger children and distinct from toys that only simulate adult activity. See Montessori at Home.
Prepared environment is a space deliberately arranged so a child can act in it independently: ordered, accessible at their height, with a limited, curated range of options rather than everything available at once. See Montessori at Home.
Sensitive period refers to a temporary window of unusually intense, narrowly focused drive toward one specific kind of learning (language or movement, for example), fading once the relevant ability is established.
Sensorial materials, used especially between ages three and six, isolate a single quality (size, colour, texture, weight, pitch) so a child can refine one kind of perception at a time.
Three-hour work cycle: an extended, uninterrupted block of time in which children choose their own work and are not moved between activities on a fixed external schedule, intended to let concentration build rather than be reset by the clock.
For one free thing to try at home, Ten Quiet Minutes is a printable sheet for watching what your child chooses, repeats and leaves.
Correction, 11 October 2026: an earlier version of this page listed 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 describes; 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.