Problem: Sentence1: The ball travelled 90 mph on his serve.
Sentence2: The mayor threw out the first ball.
Q: Does the term ball mean the same thing in both these sentences?

Answer: the same meaning

Problem: Sentence1: Don't run that software unless you have permission.
Sentence2: Run rogue.
Q: Does the term run mean the same thing in both these sentences?

Answer: different meanings

Problem: Sentence1: An idea is not a unit that can be moved from one brain to another.
Sentence2: He was a member of a special police unit.
Q: Does the term unit mean the same thing in both these sentences?

Answer: different meanings

Problem: Sentence1: They proposed a new direction for the firm.
Sentence2: He checked the direction and velocity of the wind.
Q: Does the term direction mean the same thing in both these sentences?

Answer:
different meanings