From Longman Dictionary of Contemporary Englishon the shelfon the shelfa) NOT DO somethingif something is left on the shelf, it is not used or considered The album stayed on the shelf for several years, until it was finally released. b) British English old-fashionedMARRY# too old to get married, used especially of women → shelf
Examples from the Corpus
on the shelf• The saga centres on the tangled love life of a 30-year-old woman, who fears she will be left on the shelf.• What was left on the shelves would not keep them alive.• The basket of flowers was on the shelf behind them.• The porcelain horse, the cactus, the blue bowl and the drinks were on the shelves.• These were on the shelf and the bottom of the safe was stacked with pocket files. 