corrugated edge of a coin
"The collector carefully examined the milling along the rim of the ancient silver dollar to verify its authenticity."
A grinding process using a mill.
"The ancient factory hummed loudly as it ground the wheat into flour through a continuous milling process."
present participle of mill
"The crowd began milling about outside the theater, waiting for the doors to open."
A surname.
"My neighbor, Mr. Milling, just moved into the house down the street."