Definition of "hold the fort" []

• To assume responsibility, especially in another’s absence. (verb)
• To maintain a secure position. (verb)

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• "He'd been out visiting a farmer's wife over in Okeford and didn't come home until half past five or thereabouts, so Mrs Cardew had had to talk to her and hold the fort until the Minister came home."
• "The RNA World theory suggests that RNA was a good enough enzyme to hold the fort until proteins evolved to take over the enzyme role, and that RNA was also a good enough replicator to muddle along in that role until DNA evolved."