What's "locked in" mean?

Native speaker’s answer
Rebecca
When something is "locked in," it means that there is no progress, movement, or flexibility. In the video, Facebook and the Australian government were "locked in" a stand-off meaning that neither one of them was willing to accept each other's terms. Ex: This is a long-term investment, and the price you pay is locked in and will not increase over time. Ex: The two enemies were locked in a battle for a very long time.