Can a "claim" have the same meaning as the word "sentence"?

Yes, in this context: A claim is a sentence that assets something to be true.

2) I am innocent of the crime
3) The moon is made of green cheese
4) A sentence can be a claim.
5) Saddam Hussein is developing nuclear weapons.

More information on claims:

http://www.uncp.edu/home/canada/work/markport/best/writing/argument.htm
Scroll down for the section on claims.

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Read the first three paragraphs.

http://pubpages.unh.edu/~dml3/guidefor.htm
Scroll down and read about the thesis.

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Yes, in some contexts, the word "claim" can have the same meaning as the word "sentence". In logic and argumentation, a claim is a statement that asserts something to be true. This is similar to how a sentence can express a complete thought or make a statement about something.

For example, consider the following sentences:

1) "I am innocent of the crime."
2) "The moon is made of green cheese."
3) "A sentence can be a claim."
4) "Saddam Hussein is developing nuclear weapons."

Each of these sentences can also be considered as claims because they are expressing something to be true.

If you want to learn more about claims in the context of argumentation and writing, you can visit the following resources:

1) Website: "A Guide to Effective Communication: Thinking, Writing, and Speaking"
Link: http://www.uncp.edu/home/canada/work/markport/best/writing/argument.htm
Scroll down to find the section on claims.

2) Website: "A Guide for Writing Research Papers"
Link: http://pubpages.unh.edu/~dml3/guidefor.htm
Scroll down to read about the thesis, which is closely related to making claims in academic writing.

These resources will provide you with additional information and explanations about claims in writing and argumentation.