Here are the relevant senses of the word from OED: - "To remain in a place, defer one's departure until something happens." - "colloquial. to wait about: to l

Here are the relevant senses of the word from OED: - "To remain in a place, defer one's departure until something happens." - "colloquial. to wait about: to linger expectantly, ‘hang about’ where something is likely to happen. Also (chiefly U.S.) to wait around." - "To defer action until some event has taken place; also with infinitive, to delay to do something." I think there's ambiguity in what's being awaited: - I think your parent comment assumes the scientists are awaiting a result - I think you assume the scientists are waiting for some mount of time to pass FWIW, when reading a headline, I'd definitely assume the first. "Scientists did other stuff for 2 years while a sample sat around" wouldn't be newsworthy enough to put in a headline. I think the headline was simply worded in a way that emphasises excitement over clarity. A clearer headline would be "Scientists conducted a two and a half year experiment to [...]".