* Decimal: A number system based on ten.
* Decimate: To kill one in ten, originally used in ancient Rome as a punishment. Now it means to destroy a large proportion of something.
* Decile: One of ten equal groups into which a population can be divided according to a particular characteristic.
* Decimetre: A metric unit of length equal to one tenth of a meter.
* Decennium: A period of ten years.
The "dec-" prefix in these words directly derives from "decimus", and the "deci-" prefix also traces back to the same root, just with a slight phonetic shift.