Question: Here is one sentence: Many children join a sports club.
Here is another sentence: Most politicians have joined a party.
Does the join mean the same thing in the two sentences?

Answer: the same meaning

Question: Here is one sentence: They were sitting by the water's edge.
Here is another sentence: They invaded our territorial waters.
Does the water mean the same thing in the two sentences?

Answer: the same meaning

Question: Here is one sentence: Don't lie to your parents.
Here is another sentence: He lies in his coffin.
Does the lie mean the same thing in the two sentences?

Answer: different meanings

Question: Here is one sentence: They say he gives good head.
Here is another sentence: 200 head of cattle and 50 head of horses.
Does the head mean the same thing in the two sentences?

Answer:
different meanings