"paracetamol" and "acetaminophen" are the same substance. The "aceta" part refers, as far as I know, to acetic acid (think "vinegar").

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The full chemical name(s) are as below. "N" and "para" refer to the shape. "acetyl" is an acetic acid, with some parts lopped off; "amino" is a nirtogen-hydrogen compound that (among other things) cause the amino acids to be called amino acids. Phenol is a cyclo-carbon.

N-acetyl-para-amino-phenol ; para-acetyl-amino-phenol