Sorry for finding this just now...

I found two sites, the first one says, that the Mayan word or prefix for 'blood' is k'u meaning 'sacred' or 'divine':
(from The Cleveland "Emblem Glyph")


The other is from glossary of Mayan words:

"K'awil: Sustenance or alms, used as an offering to the gods. It could be any precious substance, such as blood, semen, sap, maize, dough, gum from trees, rubber, and so on."
(from civilization.ca)