The phrase "new grandmother" refers to a woman who has recently become a grandmother, usually because her child or child-in-law has had a baby. Full definition
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Relatives who want to help can be a mixed blessing because new grandmothers or aunts can sometimes push a father into the background. (babycenter.com)
As an active and asymptomatic recently retired, exceedingly proud new grandmother, Linda Wilkinson was completely taken aback by the diagnosis of Stage 4 lung cancer. (sciencedaily.com)