Longman Dictionary of Contemporary English
Douglas Harper's Etymology Dictionary
in the metric system, word-forming element denoting weights of one-tenth of the standard unit of measure, 1801, from French deci-, taken arbitrarily from Latin decimus "tenth," from decem "ten" (see ten).
pre. 1 Meaning a tenth part. 2 In the International System of Units and other metric systems of units, multiplying the unit to which it is attached by 10-1. Symbol: d
Deci- (symbol d) is a decimal unit prefix in the metric system denoting a factor of one tenth. Proposed in 1793 and adopted in 1795, the prefix comes from the Latin , meaning "tenth". Since 1960, the prefix is part of the International System of Units (SI). Its most frequent use, however, is in a non- SI unit, the decibel, used to measure sound intensity (relative to a reference) and many other ratios.
- A compact disc is about 12 centimeters or 1.2 decimeters.