[Diamond]

Mary is the Mother of Jesus.

Jesus is God.

Therefore, Mary is the Mother of God.

When a word or words change meaning in the usage of an argument the result is the fallacy of equivocation. The problem with the syllogism above is the ambiguity in the meaning of the words, "God" and "mother".

It's like saying:

Jesus is God.
God is a Trinity.
Jesus is the Trinity.

Cordially,

[Arthur McGowan]

There’s no ambiguity involved.

Mary is the mother of Jesus.
Jesus is God, the Second Person of the Trinity.
Mary is the mother of God, the Second Person of the Trinity.

[Arthur McGowan]

There is no equivocation occurring in the following syllogism:

Mary is the mother of Jesus.
Jesus is God.
Mary is the mother of God.

The word “God” has exactly the same meaning in the second and third propositions: the Second Person of the Trinity.

The word “mother” has exactly the same meaning in the first and third propositions: ...one who conceived in her womb and gave birth to...