Why Is a ‘Nest Egg’ Tied to Money?

A nest egg is “a fund of money accumulated as a reserve,” often set aside for long periods of time and invested so it grows along the way. This fund can be feathered with high-yield savings accounts, retirement accounts, and certificates of deposit, all of which go toward helping people achieve long-term financial goals. But before “nest egg” related to personal finances, it had a more literal meaning in the context of poultry farms.

The original definition for “nest egg” was “a natural or artificial egg left in a nest especially to induce a hen to continue to lay there.” This is a farming technique that dates back to the 14th century. Farmers would place decoy eggs in nests to attract hens, thereby encouraging them to efficiently produce more plentiful amounts of eggs.

By 1686, the meaning of “nest egg” had evolved to be used in the financial context that we so closely associate it with today. According to the Oxford English Dictionary, an early citation is found in correspondence between philosopher John Locke and his friend Edward Clarke. The letter read, “The rest, I perceive, he is not trouble should remain as a nest egg till a farther occasion,” referring to an amount of money that shouldn’t be touched until a further date. It’s worth noting that this letter wasn’t widely published until 1927, so it probably didn’t play much of a role in popularizing the phrase. However, it still serves as early evidence of the phrase being used in its monetary context.

How the phrase evolved from decoy eggs to retirement accounts isn’t entirely certain, but there’s a natural connection between the former and the latter. Placing decoy eggs in a nest could lead to bountiful gains down the line, which is exactly what people hope happens when they put money into their 401(k)s.