The two terms are very popular in my locality. According to my teacher,
overthrow: is when fielder near the pitch misses throw from fielder at far off in field.
He defined "throw-by" as the event when "batsman has not touched the ball with his bat or gloves or any part of his body, he attempts run, fielder throws ball but misses run out"
Surprisingly, I found no mention of "throw-by" on the internet or in the laws as my teacher said.
Did he confuse "throw-by" with another popular terminology? Or is there really some "throw-by" phenomenon, conspicuously absent from the internet?