Hi Ritva,
R: "A determinative does not necessarily represent literally the object described. It denotes the nature of the object, the idea behind it, it's category. The house-glyph is used in many contexts as a determinative, and yet it does not in all cases mean "a house". A regular tomb written using "house" as a determinative. The word tomb being written mostly with the house-determinative is a good example of this. Why should it be different for the pyramid-glyph as determinative?"
I gave my view on this question here: [
www.hallofmaat.com]
CT: "As I understand it, the determinative indicates the general idea of the word - in the case of a non royal tomb, O1 indicates 'house' / 'dwelling place' - specifically the tomb owners 'house' for eternity. In the case of a royal pyramid, O24 as the determinative in the name of the pyramid, indicates 'pyramid' - specifically in the case of an OK royal tomb - the king's 'house' for eternity with its distinctive pyramid form that sets it apart from commoners tombs.
O24 is used in the name of the kings pyramid, and the pyramid is a manifestation of the king.
Strictly speaking, originally the name of the pyramid was not the name of the cemeteries around the royal funerary complex - the cemeteries were the cemetries of Akhet Khufu - they were not Akhet Khufu. The royal cult complex is not Akhet Khufu, but the royal cult complex of Akhet Khufu."
Perhaps the reason the 'pyramid' ideogram was originally used exclusively for the pyramid, is that the pyramid has such a distinctive form, clearly seen in the ideogram that represents it.
The 'house' sign is simply the plan of a building with an interior space, so it could refer to any building, tomb, house, etc. or in the sense of 'dwelling' somewhere.
CT