Question

What's the English for 13-летие

Answer 1

Thirteenth birthday
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Answer 2

The English equivalent for "13-летие" is "13th anniversary" or "13th birthday," depending on the context. If you are referring to the 13th anniversary of an event or a milestone, you would use "13th anniversary." If you are talking about someone turning 13 years old, you would use "13th birthday."