Deci- followed by deca
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 decimus, meaning "tenth". Since 1960, the prefix is part of the International System of Units (SI).A frequent use of the prefix is in the unit deciliter (dl), common in food recipes; many European homes have a deciliter measure for flour, water, etc. A common measure in engineering is the unit decibel for measuring ratios of power and root-power quantities, such as sound level and electrical amplification.