connection vs coherency

connection and coherency both are nouns.

Word	Noun	Adjective	Verb	Adverb
connection	Yes	No	No	No
coherency	Yes	No	No	No

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

connection (noun)	coherency (noun)
the act of bringing two things into contact (especially for communication)	logical and orderly and consistent relation of parts
shifting from one form of transportation to another	the state of cohering or sticking together
an instrumentality that connects
the process of bringing ideas or events together in memory or imagination
a supplier (especially of narcotics)
(usually plural) a person who is influential and to whom you are connected in some way (as by family or friendship)
a relation between things or events (as in the case of one causing the other or sharing features with it)
a connecting shape
the state of being connected