The warm, vicarious gladness some people feel when a partner is happily involved.
The warm, vicarious gladness some people feel when a partner is happily involved — romantically or sexually — with someone else; frequently described as jealousy's mirror image.
Its whole point is to stand opposite jealousy and the urge to possess. And unlike a general gladness at anyone's good news (cf. Buddhist mudita), it is pinned specifically to a partner's other romantic or sexual connections.
Coined English; not a classical borrowing. Probably modeled on “dispersion.”
Coined by the Kerista Community (a San Francisco commune) in the 1970s, probably modeled on “dispersion.” Alternative Latin/French derivations are rated less likely.
A recent neologism from 1970s communal/polyamory subculture; it spread through polyamory communities and is documented in print from the late 1990s. NOTE: it is not listed in most standard dictionaries — it appears in Wiktionary (labeled “neologism”) and Wikipedia, but not as a standard Merriam-Webster or OED headword.
MODERN NEOLOGISM: A subcultural term, not yet standard-lexicalized. Origin and community usage are well documented, but it is absent from the major standard dictionaries checked.