"one-shot" usually just means, one example and its correct answer was provided in the prompt.

See also, "zero-shot" / "few-shot" etc.

I've seen one-shot used to mean two different things in LLMs:

1. Getting an LLM to do something based on a single example

2. Getting an LLM to achieve a goal from a single prompt with no follow-ups

I think both are equally valid.