1.
thirty years old; one's thirties
An old-fashioned or literary way of saying thirty years of age. In modern usage, it often appears in casual conversation with a slightly humorous or dramatic tone, especially when talking about turning thirty as a milestone.
Etymology
From classical Japanese counting, where 三十 was the native Japanese word for thirty and 路 indicated age. Similar archaic age words exist: 二十路 (twenty) and 四十路 (forty).
Usage
Although archaic in origin, 三十路 is commonly used in modern casual speech, often with a humorous or self-deprecating tone when someone is lamenting or joking about turning thirty.