This word derives from the Medieval Latin secretarius, which is based on the Latin secretum, or secret. The original meaning is someone employed to handle confidential or secret business. From John de Trevisa’s 1387 translation of Polychronicon Ranulphi Higden:
Þanne his secretarie [L. secretarius] tolde hym what he hadde i-seie and i-doo.
(Then his secretary told him what he had said and done.)
By the 15th century, the word was being used in the sense of someone who handled the correspondence of another. In early use, it was usually in reference to a servant of the king and was mixed with the earlier sense of one who handles confidential affairs. From the Romance of Sir Beues of Hamtoun:
Kyng Armyne...cawsyd hys secretory a lettyr to make.
This sense evolved in two separate directions. On the one hand, secretary came to mean a clerk who handles mundane matters for someone important and on the other it came to mean a high-ranking government official empowered to act in affairs of state, a minister of the crown or, in the US, the president. By 1599, the term was being used as the official title of such high officials, as in secretary of state or principal secretary.
(Source: Oxford English Dictionary, 2nd Edition)
Copyright 1997-2015, by David Wilton