To acknowledge oneself beaten; to eat umble pie. A maritime expression. When a ship in fight or on meeting another ship, lets down her topsails at least half-mast high, she is said to strike, meaning that she submits or pays respect to the other.
Now Margaret Must strike her sail, and learn a while to serve When kings command.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894