The phrase "a notch in a" is correct and usable in written English.
It is typically used to indicate an achievement or a mark of progress in a particular context, often implying that it is part of a larger journey or series of accomplishments.
Example: "Winning this award is just a notch in a long journey towards my career goals."
Alternatives: "a step in a" or "a milestone in a".
This is as automatic as carving a notch in a stick.
"When I met him, the rhythm in the room went down a notch — in a good way".
He was taking a reporter out to Comanche Gap, a notch in a spiny-backed ridge of black rock, a place where there are hundreds of Indian rock carvings called petroglyphs.
The local stress distribution near a notch in a compact tension specimen was measured in situ by the combination of an X-ray stress analysis and a custom-designed load device.
Mitt Romney is taking his attacks on Newt Gingrich up a notch in a new television ad that tries to link him to the implosion of the housing market.
The stress field around a notch in a coarse grained Mg AZ31 sample has been measured under tensile load using the individual grains as probes in an in situ high energy synchrotron diffraction experiment.
Mr. Darnell, who told The Wall Street Journal in October that his competitors would give "one eye and two legs" to have "The X Factor" on their schedules, stepped it up a notch in an interview last week, saying without being prompted, "All the networks would literally give all their arms, legs and one eye for a show like this".
Nicole Sperling of Entertainment Weekly gave the book a B+ and said, "Collins has kicked the brutal violence up a notch in an edge-of-your-seat plot".
"Fans will be happy to hear that 'Mockingjay' is every bit as complex and imaginative as 'Hunger Games' and 'Catching Fire.' Collins has kicked the brutal violence up a notch in an edge-of-your-seat plot".
His voice rises a notch, in the manner of a motivational speaker.
It is hard to see that going up a notch in scale would make a qualitative difference).
