In most contexts, god is capitalized, while deity is not. It seems to me that god is a generic name equivalent to deity. My POV is that English speaking Christians are chauvinistic or perhaps arrogant in requiring that god be capitalized in most contexts. Exceptions: Name a Greek god. Deity is a synonym for god.
The English word "god/God" has two basic meanings.
- 1. (Always lower case in edited writing) Any of the multiple deities in a polytheistic religion or philosophy, often reigning over a specific portion or aspect of the universe, such as "Ares, the god of war." In this usage, the word "god" invariably takes a definite or indefinite article: the god or a god. It is a common noun, not a proper name.
- 2. (Always upper case in edited writing) The single deity in the monotheistic Abrahamic religions most familiar to anglophones: Judaism, Christianity, Islam, Rastafarianism and (arguably) Baha'i. In the context of Islam, the Arabic translation "Allah" is preferred both by editors and in vernacular speech. Rastafarians prefer the name "Jah" but are comfortable with "God." (Other monotheistic religions are virtually unknown among anglophones so there is no style standard for writing the names of their deities.) In this usage, the word "God" never takes an article except as required for more complicated syntax such as "the God of the Israelites." It is a proper name, not a common noun.
So your cue is: If it takes an article, then it refers to one of many gods, so it is a common noun and is written in lower case. If it stands alone with no article, then it is the single deity of one of the monotheistic religions, so it is a proper name and is written in upper case.
In venues such as SciForums, where hostility to religion is at least common and perhaps even the majority opinion, and furthermore where there are few editorial standards of style, members are free to write "god" in lower case even when referring to the God of Abraham, as a deliberate insult to Abrahamists.
But if they are misunderstood, the Linguistics Moderator (who in real life is a writer and editor) will not rescue them.
What about other Christian languages? Is dieu capitalized? Does French have any synonyms for dieu?
The French capitalize
Dieu when it means God and write lower case
dieu when it means god.
Dios is capitalized in Spanish and
Deus in Portuguese. In both languages
el dios/o deus or
un dios/um deus is written in lower case, referring to one of multiple gods in a polytheistic religion. Spanish has the word
deidad, the same Latin word from which we get "deity." Since we got that word via French, the French still have it:
déité. The Portuguese use the word
divinidade instead, the etymological equivalent of our word "divinity": the quality of godhood, not the white fudge.
