ology vs symbology

ology and symbology both are nouns.

Word	Noun	Adjective	Verb	Adverb
ology	Yes	No	No	No
symbology	Yes	No	No	No

As nouns, symbology is a hyponym of ology; that is, symbology is a word with a more specific, narrower meaning than ology:

ology: an informal word (abstracted from words with this ending) for some unidentified branch of knowledge
symbology: the study or the use of symbols and symbolism

ology (noun)	symbology (noun)
an informal word (abstracted from words with this ending) for some unidentified branch of knowledge	the study or the use of symbols and symbolism