I note that when someone is knighted these days, they are provided with a little stool with an attached handle to facilitate kneeling before the monarch.
It seems like a nice touch; personally, I would have some difficulty in going down to a full kneel and then getting upright. It would certainly be an awkward maneuver for me, and I suspect for many who receive the accolade.
Accolade was first used in 1611 and is French, from the Occitan acolada. This, in turn, came from the Latin ad ("to") + collum ("neck") and in Occitan originally meant "embrace". From about 1852, the meaning of "accolade" was extended to mean "praise" or "award" or "honor.I tried to search for more information on that little stool, but can't find a discussion or even whether it has a proper name.
The blow, or colée, when first utilized was given with a naked fist. It was a forceful box on the ear or neck that one would remember. This was later substituted for by a gentle stroke with the flat part of the sword against the side of the neck. This then developed into the custom of tapping on either the right or left shoulder or both, which is still the tradition in Great Britain today.
Addendum: A hat tip to Ran, whose search revealed that the press sometimes refer to this as a "knighting stool," but the royal family's website calls it an "investiture stool" (and they keep a spare one on their yacht).
Photo of Sir Patrick Stewart via TrekMovie.com.