What does deciare mean?
The deciare is a small unit of area in the metric system, equal to one tenth of an are — that is, ten square metres. It belongs to the family of metric land measures built on the are (one hundred square metres) and its larger relative, the hectare (one hundred ares), all introduced with the French metric system at the end of the eighteenth century. Like its relatives, it takes its name from the Latin prefix deci-, meaning 'tenth', combined with the unit it subdivides. In practice the deciare has always been overshadowed by the square metre and the hectare, and today it survives chiefly in older surveying records, technical literature, and dictionaries of units rather than in everyday speech. A gardener describing a plot of two or three deciars would be referring to a space of only twenty or thirty square metres — a reminder of just how fine-grained the original designers intended the metric scale of land measurement to be.
nounA metric unit of area equal to one tenth of an are, i.e. ten square metres.
- A metric unit of area equal to ten square metres, one tenth of an are.
"The allotment measured roughly two and a half deciars, barely enough for a modest vegetable patch."
"The surveyor recorded each plot in deciars rather than the more familiar square metres."
"A garden of five deciars provides enough space for a small orchard."
The standard plural simply adds -s, consistent with most metric unit names borrowed into English.
"Each of the three fields covered about forty deciars."
The deciare is so obscure that even many dictionaries skip it — yet it was part of the original French metric system's plan to divide the are into neat tenths.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of deciare
The word 'deciare' derives from the Latin prefix deci-, meaning 'a tenth', attached to the are, the base metric unit of area adopted during the French Revolution's reform of weights and measures in the 1790s. It thus denotes one tenth of an are, or ten square metres, alongside related formations such as centiare and deciare's larger counterpart, the hectare. The prefix deci- itself comes from Latin decimus, 'tenth', the same root that gives English words like decimal and decade. The term has remained largely confined to technical and lexicographic use since its introduction.
How deciare is actually used
The deciare is extremely rare in modern usage, appearing mainly in historical or technical contexts relating to the metric measurement of land; the square metre and hectare have largely displaced it.
Easily confused with deciare
A deciliter is a unit of volume equal to one tenth of a litre, whereas a deciare is a unit of land area equal to ten square metres.