colonel

The word comes from 1540s Middle French coronnel, from Old Italian colonnello, meaning the officer who led the 'column' company at the head of a regiment. That Italian word traces to compagnia colonnella, 'little column company,' from Latin columna, 'pillar,' ultimately from a Proto-Indo-European root meaning 'to rise, be elevated.'

English spelling was reformed in the 1580s to match the Italian colonnello, even as people kept pronouncing it with an 'r' in speech. Both pronunciations coexisted until around 1650, when the 'r' sound won out for good, leaving the word spelled one way and said another.

It shares its root with columna, 'pillar,' connecting it to English hill and holm, both descended from the same Proto-Indo-European root for rising or standing prominent.