Definition from Wiktionary, the free dictionary
- Early in the morning.
- I'll meet you first thing at the station.
- Straight away, very soon.
1913, Joseph C. Lincoln, chapter 1, Mr. Pratt's Patients:
- I stumbled along through the young pines and huckleberry bushes. Pretty soon I struck into a sort of path that, I cal'lated, might lead to the road I was hunting for. It twisted and turned, and, the first thing I knew, made a sudden bend around a bunch of bayberry scrub and opened out into a big clear space like a lawn.