colonelyoudaoicibaDictYouDict[colonel 词源字典]
colonel: [17] Historically, a colonel was so called because he commanded the company at the head of a regiment, known in Italian as the compagna colonnella, literally the ‘little-column company’; hence the commander himself took the title colonnella. The word colonnella is a diminutive form of colonna, which is descended from Latin columna ‘pillar’ (source of English column).

It appears first to have entered English via French in the form coronel, in which the first l had mutated to r. Spellings with this r occur in English from the 17th and 18th centuries, and it is the source of the word’s modern pronunciation. Colonel represents a return to the original Italian spelling.
=> column[colonel etymology, colonel origin, 英语词源]
colonel (n.)youdaoicibaDictYouDict
1540s, coronell, from Middle French coronel (16c.), modified by dissimilation from Italian colonnella "commander of a column of soldiers at the head of a regiment," from compagna colonella "little column company," from Latin columna "pillar" (see column). English spelling modified 1580s in learned writing to conform with the Italian form (via translations of Italian military manuals), and pronunciations with "r" and "l" coexisted 17c.-18c., but the earlier pronunciation prevailed. Spanish coronel, from Italian, shows a similar evolution by dissimilation.