Glennafeminine form of Glenn, it's one of the oldest names on record apparently, but I don't think it sounds too old-fashioned. I like it 'cos I know a woman called Glenys, but I don't like that 'cos it's too dated. Glenna would fit into the 21st century much better!
Glenna was probably coined in the 20th century as a feminine form of Glenn.
See Also: Glenn (boy), Glenn (girl)
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