To start at the beginning, a holorime is, in its simplest form, a poem composed of two lines, both of which sound the same but mean quite different things. It's easier in French than in English, and here is one which was supposedly written by Victor Hugo:

Gal, amant de la Reine, alla (tour magnanime)
Gallament de l'Arène à la Tour Magne, à Nîmes.

The holorhyme, or charade, is a kind of untangled pun, but it does not pun. One series of letters is given twice, but different words are assembled with them, giving two different meanings.