The phrase "a half rotation" is correct and usable in written English.
It can be used in contexts related to movement, mechanics, or geometry, where you want to describe a rotation that is 180 degrees.
Example: "To align the gears properly, you need to make a half rotation of the knob."
Alternatives: "180-degree turn" or "half turn".
The tube has roughly performed one and a half rotation on the substrate surface.
To obtain the 3D image, two hundred averaged projection images were recorded over a half rotation.
The 3D absorbed energy distribution in the hind leg of the mouse was obtained by recording one hundred projection images over a half rotation.
Applying the inverse Radon transform to a set of projections recorded over a half rotation of the sample provides 3D photoacoustic tomography images in less than one minute with a resolution below 100 µm.
He landed six 540-degree spins — one and a half rotations — and included a 720, two full rotations.
Some skiers have landed 1660-degree spins (four and a half rotations), although without the necessary stylish grab to win a competition.
He pulled a backflip over the gap and soared 20 feet above the quarterpipe, pulling a 540 spin (one and a half rotations), twisting the board beneath him.
One trick Jankowski said to watch for next winter was a double-corked 1260, a spin cycle of three and a half rotations and two off-axis flips.
Bestwick, 37, pulled a series of flairs and soaring 540 spins (one and a half rotations) after falling hard on an earlier run.
In 1999, Tony Hawk pulled the sport's first 900-degree spin (two and a half rotations) on a vert ramp at the X Games, catapulting him and the Games into the mainstream.
Lexi, he says, is already "spinning 5's" — referring to a 540, or making one and a half rotations — and is comfortable "riding switch," with her weaker leg forward, a requisite of top riding that typically takes years to master.
