There is a technical distinction according to Coe between the Mayan glyphs and hieroglyphs. IIRC, the Mayan glyphs express phonemes while hieroglyphs represent words.
The systems have different constructions, but they are both “hieroglyphs” due to the religious association. Egyptian hieroglyphs have phonetic content as well as some ideographic use. All writing systems convey phonetic information, according to Dr. Zender (see below).
I am presently listening to “Writing and Civilization: From Ancient Worlds to Modernity,” by Professor Marc Zender of Tulane U. (in the car) and “Maya to Aztec: Ancient Mesoamerica Revealed,” by Professor Edwin Barnhart of the University of Texas (in the kitchen). Both reference the Coe book, which wasn’t at the library today but certainly will be when I go back next Tuesday.