Deci

Part of speech: noun, prefix

Definitions

1. A metric prefix denoting a factor of one-tenth
2. Representing a division into ten equal parts, often used in measurements
3. A term used in the decimal system to indicate a scale reduction by a factor of ten

Etymology: The prefix "deci" comes from Latin "decimus", meaning "tenth", which is also the source of English "decimal" and "decimate" (originally to kill one man in ten as a punishment in Roman military discipline). Its modern life is far more recent. It was adopted into the International System of Units when the metric prefixes were formalised in 1795 and then settled by the General Conference on Weights and Measures in 1960, when "deci" was fixed as the prefix for a factor of one-tenth, written "d". The prefix was not coined from scratch to name fractions. It was built by the French metric reformers, who chose Latin and Greek number roots for the new system. Bel and decibel show how it travels: the decibel was named after Alexander Graham Bell, and the "deci" part marks it as one-tenth of a bel, a unit that itself was too large for most practical use.

Synonyms: tenth, deci- (prefix)