toehold

noun

1. A foothold small enough to support just the toe.
2. (broadly)Any small advantage which allows one to make significant progress; a slight footing or foothold.

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

   “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.”

   “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.”

   “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.”

3. A hold in which the aggressor bends back the opponent's foot.