From Proto-Indo-European *kʷel- (“to move; to turn (around)”). See Latin colō for more.
τέλος • (télos) (genitive τέλεος or τέλους); n, third declension;
- completion, accomplishment, fulfillment, perfection, consummation
- result, product
- end of life: death
- boundary, border, extremity
- supreme power
- the highest government office: magistrate
- that which is ordered to be done: task, duty
- money paid to the government: tax, toll
- a person's property, according to which he was classed
- thus, generally: rank, class
- unit of soldiers: legion, company
- initiation (especially into mystery religions)
- mystery religion
- any religious ceremony
This inflection pattern originally had a sigma (i.e. *τέλεσος), which was dropped early on in the history of Ancient Greek.
The irregular accentuation of this paradigm is explained by the fact that it is the contracted version of the above paradigm.