dogma: a tenet or code of tenets; a doctrine or body of doctrines formally proclaimed by a church

(tenet: one of the principles or doctrines held in common by members of an organized group.)

(doctrine: something that is taught; dogma, tenet.)

ethos: the distinguishing character, moral nature, or guiding beliefs of a person, group, or institution.

You are right that they are similar. The shade of difference here is that tenets are simply the beliefs – something that can be boiled down to a statement or set of statements. The ethos encompasses beliefs with more than that. It attempts to include the nature of a group.

I was having a hard time explaining it right based on that definition, so I looked up the etymology of ethos: The characteristic spirit of a people or community.

I find spirit to be something that is hard to define, something that can’t be boiled down to a set of statements, yet something that can include a set of statements as a part of what shapes that spirit.

There is a difference between doctrine and dogma. Doctrines are official teachings of the Catholic Church. They are not necessarily definitive teachings (i.e. infallible teachings). A doctrine that is taught as definitive (infallible) is called a dogma. All dogmas are doctrines, but not all doctrines are dogmas. Doctrines may change but our belief is that dogmas are always true and will never become untrue. That does not mean that the way they are stated does not change. Some dogmas are restated and refined in language because of cultural changes that have happened since they were originally stated.

dogma means…….

1.a system of principles or tenets, as of a church.

2.a specific tenet or doctrine authoritatively laid down, as by a church: the dogma of the Assumption.

3.prescribed doctrine: political dogma.

4.a settled or established opinion, belief, or principle.

and

ethos means

Sociology. the fundamental character or spirit of a culture; the underlying sentiment that informs the beliefs, customs, or practices of a group or society; dominant assumptions of a people or period: In the Greek ethos the individual was highly valued.

2.the character or disposition of a community, group, person, etc.

3.the moral element in dramatic literature that determines a character’s action rather than his or her thought or emotion.

does it really matter?its not like youll use them