A somewhat colloquial or informal term for an unmarried woman, often used in media or casual conversation. Can carry a slight nuance of independence or being past the typical marriage age, but not inherently negative.
Recently, events for single women have been increasing.
She enjoys a free life as a single woman.
Abbreviation of 独身女性 (どくしんじょせい, 'unmarried woman'). The exact origin is uncertain, but it likely emerged in colloquial Japanese as a concise label.