Definition of "toehold"

Were Herat to fall to the Persians, this would give the Russians a crucial and dangerous toe-hold in western Afghanistan.

1990, Peter Hopkirk, The Great Game, Folio Society, published 2010, page 151

The tiny old houses and flats of this once impoverished quarter had mostly been refurbished into toeholds for young Atlantans from all around the Anglosphere, poor in equity but rich in expectations, who had come to the great city to incubate their careers.

1995, Neal Stephenson, The Diamond Age, Bantam Spectra, page 373

One in three "adult-kids" who have not left the parental nest say they are still living at home because they cannot afford to get a toehold on the property ladder by buying or renting.

2009 December 8, Alan Travis, “More young adults in 20s and 30s living with parents than in past 20 years”, in The Guardian‎

Strachey argued that the Raj was bad for Britain and the British. In Inglorious Empire, Shashi Tharoor argues, with equal passion, that it was much worse for India and the Indians. In 1700, when the British were mere traders clinging on to a few coastal toeholds, the Emperor Aurangzeb ruled over a country that accounted for a quarter of the world’s economy.

2017 September 7, Ferdinand Mount, “Umbrageousness”, in London Review of Books‎