Ironically polite term for a woman who does not want her actual age known, e.g. one who is close to or just over the menopause.
Things which define women of a certain age are: exceptionally gaudy clothing, homeopathy and aromatherapy, sensible haircuts, books on feminism, affairs with paper boys, and coffee mornings.
Your mum is a woman of a certain age. Yes she is.
18👍 37👎