There's a bug with the Headword indexing in Merriam-Webster’s Collegiate Dictionary (Eleventh Edition). It might be a resource bug, I'm not sure.
Searching for {Headword glossolalia} returns all the words between glossolalia and gorgonize.
Searching for {Headword gorgonize} returns all the words between gorgonize and Gorgonzola.
Searching for {Headword Gorgonzola} returns all the words between Gorgonzola and Graeco.
Lots of other words work fine.