No Spanish
The word ‘dimensions’ is not a Spanish word, it is actually English and it has a few meanings. It can mean the aspect of a feature of a situation, the measurements of something, or of course other dimensions in space and time. Actually, it is a very useful word that is widely used.
That is why we are surprised that this person claims to have never seen it before in their life. They automatically thought that this was a word from the Spanish language. Ignorance like this is something that we have not seen in a while, it doesn’t even look like a Spanish word.