Webster's Revised Unabridged Dictionary · 1913

Usher

Usher , noun

[Old English ussher, uschere, Old French ussier, uisser, oissier, hussier, huissier, from Latin ostiarius a doorkeeper, from ostium a door, entrance, from os mouth. See Oral, and compare Ostiary.]

1.
An officer or servant who has the care of the door of a court, hall, chamber, or the like; hence, an officer whose business it is to introduce strangers, or to walk before a person of rank. Also, one who escorts persons to seats in a church, theater, etc.
The ushers and the squires. — Chaucer
These are the ushers of Marcius. — Shakespeare

There are various officers of this kind attached to the royal household in England, including the gentleman usher of the black rod, who attends in the House of Peers during the sessions of Parliament, and twelve or more gentlemen ushers. See Black rod.

2.
An under teacher, or assistant master, in a school.

Usher , transitive verb

To introduce or escort, as an usher, forerunner, or harbinger; to forerun; -- sometimes followed by in or forth; as, to usher in a stranger; to usher forth the guests; to usher a visitor into the room.
The stars that usher evening rose. — Milton
The Examiner was ushered into the world by a letter, setting forth the great genius of the author. — Addison