Definition of "Gretta"

"Gretta tells me you're not going to take a cab back to Monkstown tonight, Gabriel," said Aunt Kate."No," said Gabriel, turning to his wife, "we had quite enough of that last year, hadn't we? Don't you remember, Aunt Kate, what a cold Gretta got out of it? Cab windows rattling all the way, and the east wind blowing in after we passed Merrion. Very jolly it was. Gretta caught a dreadful cold."

1914 June, James Joyce, “The Dead”, in Dubliners, London: Grant Richards

Mrs Saunders referred to Aoife throughout this talk as 'Eva' and when Gretta corrected her, Mrs Saunders replied that didn't Gretta think it would be better 'for everyone' to use what she termed 'the proper spelling' of the name? If only to give Eva a better chance of learning to write it?

2013, Maggie O'Farrell, Instructions for a Heatwave, Tinder Press, page 79