
1) Catholic clerical clothing 2) Italian feminine given name 3) Military insignium
Found on
https://www.crosswordclues.com/clue/greca

The greca, or more properly the douillette, is a clerical double-breasted overcoat worn over the cassock. The greca is slightly longer than the cassock so as to entirely cover it. The greca is black except in the case of the Pope who wears a white greca. The black greca may have either a plain or velvet collar. The greca is usually worn in place o...
Found on
http://en.wikipedia.org/wiki/Greca

acronym: Group of Experts on Accident Consequences (NEA and OECD)
Found on
https://www.encyclo.co.uk/local/20002
No exact match found.