What does decimetre mean?
A decimetre is a metric unit of length equal to one tenth of a metre, or ten centimetres, abbreviated as dm. It occupies an awkward middle ground in everyday measurement — larger than the centimetres people commonly cite but smaller than the metre that dominates daily life — so it sees less casual use than its neighbouring units. Nevertheless, it remains standard in scientific notation, European school curricula, and technical measurement. Its most celebrated role is in volume: a cube with sides of exactly one decimetre encloses precisely one litre, making the cubic decimetre the direct link between the metric units of length and capacity. The word follows the Latin-derived pattern of metric terms, combining the prefix deci-, meaning one tenth, with metre. Spelled "decimeter" in American English, it carries no figurative or emotional connotations; it is purely a neutral, precise term of measurement used wherever decimal subdivision of the metre is convenient.
nounA unit of length in the metric system equal to one tenth of a metre, or ten centimetres.
- A metric unit of length equal to one tenth of a metre (10 cm), symbol dm.
"The seedlings were spaced a decimetre apart along the row."
"The textbook asked students to measure the width of their notebook in decimetres."
"A cube measuring one decimetre on each side has a volume of exactly one litre."
In American English, spelled "decimeters."
"The shelf was two decimetres too wide for the alcove."
A cubic decimetre of water is exactly one litre — which is why the humble dm hides inside every bottle you buy.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of decimetre
The word "decimetre" was coined in France in the 1790s during the creation of the metric system, formed from the Latin prefix deci- ("tenth"), from decimus, combined with "metre," itself from the Greek metron ("measure"). Like its sibling terms centimetre and millimetre, it entered English as part of the international adoption of French metric vocabulary in the nineteenth century. Cognate formations using the same Latin root include "decimal," "decimate," and "decibel."
How decimetre is actually used
Spelled "decimeter" in American English and "decimetre" in British English. The unit is relatively uncommon in everyday use compared with centimetres and metres, but it appears frequently in scientific, educational, and technical contexts, especially in Europe. The derived units square decimetre (dm²) and cubic decimetre (dm³) are used for area and volume; notably, one cubic decimetre equals one litre by definition.
Easily confused with decimetre
"Decimeter" is simply the American spelling of the same word; "decimetre" is the British spelling.
A decametre is ten metres, whereas a decimetre is one tenth of a metre — the prefixes deca- and deci- point in opposite directions.