In which sense is the word arc used in the following sentence? I look forward to your feedback.
http://www.3sixty.com/persephone/
Vegetation and harvest goddesses are a common arc in mythologies, and similar tropes appear across cultures. Persephone’s cult of worship pre-dates the full story of the Olympic gods, worshipped in some form by agrarian cults.
It’s used in the sense of a “story arc” or “narrative arc,” referring to the traditional narrative structure of increasing conflict followed by a resolution.
Thanks friedo. Very helpful
Misused, I’d say, since “vegetation and harvest goddesses” are images, perhaps a theme, but not a story. Persephone-and-Hades is a story.
FWIW, I agree. “A common element,” maybe, but the word “arc” doesn’t really make sense in that context.
That was my feeling too. So how should it have been phrased?
A common (or, frequent) figure/component/characterization/symbol.
Especially when put in the close company of “trope” it sounds like overuse of neologism. As Peremensoe points out, the story arc would be something that the goddesses do or that happens to them.
So, “Vegetation and harvest goddesses are a common figure in mythologies, and similar themes appear across cultures.”
OR, to make use of arc, “The journeys or travails of vegetation and harvest goddesses as a representation of seasons are a frequently seen arc in mythologies, [etc]”
“Archetype”.
Great call. That is exactly it.
An archetype is more than just an image, it’s a “universal image”. Something that tends to be common to all (or most) cultures. This is a key element of Jungian Psychological Theory. I’m sure the writer just suffered a Freudian slip. 
So that sentence should have read:
“Vegetation and harvest goddesses are common archetypes in mythologies, and similar tropes appear across cultures. Persephone’s cult of worship pre-dates the full story of the Olympic gods, worshipped in some form by agrarian cults.”
Thank you all.