the.com/beachhead

means An initial foothold or small secured position you establish first, so you can safely build on it and expand from there.

from Straight out of WWII military jargon — a literal beachhead was the stretch of coastline an invading force seized and held, often at brutal cost, so that reinforcements, tanks, and supplies could pour in behind them. The word fused 'beach' with 'bridgehead' (a position held at the far end of a bridge or river crossing to protect the crossing itself). By the mid-20th century it had marched off the sand and into boardrooms and business plans, where 'establishing a beachhead' in a market means the same thing minus the gunfire: grab the small, defensible spot first, then expand.