Discussing the etymology of words can be a useful strategy for increasing students’ vocabulary and the correct spelling of related words.
Words containing the root ‘dec’ meaning ‘ten’ comes from both Latin (decem) and Greek (deka).
In the metric system ‘deci’ is used to denote 1/10th of a standard unit of measure (decimal = deci + the suffix ‘al’ meaning ‘pertaining to’). A decimeter (deci+meter) is a measure of length equal to one-tenth of a meter. The decimal point was first introduced in 1711 by John Napier, a Scottish mathematician.
In 1924, the term ‘decibel’ (deci+bel) was coined to describe the efficiency of telephone circuits. ‘Bel’ is a measurement of power quantity and was named after Alexander Graham Bell who is credited with inventing the first telephone. However, a ‘bel’ is rarely used as it is larger than needed in most circumstances. A decibel is 1/10th of a bel.
The word decimate is linked to the punishment used by the Romans whereby one in every ten people was executed as a way of controlling a rebellious city or large groups guilty of offences such as cowardice, mutiny, desertion or insubordination.
Although we now consider December the 12th month of the year, in the old Roman calendar, which began with March, it was considered the 10th month of the year. The winter days following December (it was in the northern hemisphere) were not included in any month.
A decade is ten years and a decalogue (logos = Greek for word or speech) is ten commandments.
A decathlon (athlon = Greek for contest) is an athletic event in which each competitor competes in ten events (100 meter sprint, long jump, shot-put, high jump, 400 meter run, 110 meters hurdles, discus, pole vault, javelin, and 1,500 meter run).
However, be careful! Just because a word begins with ‘dec’ does not mean that it is related to the root word ‘dec’ meaning ten. For example, there are many words beginning with a ‘c’ to which the prefix ‘de’ (meaning down or away) has been added (decide, decipher, deciduous, deceive, decoy, decadent).