No, Full HD is 1920 x 1080P, that’s the defined standard for what Full HD means
Full HD is also a widescreen aspect ratio, of which there are many different kinds
That does not change the fact that if you have a full screen, i.e. 1.33:1 aspect ratio on a Full HD medium, it’s still gonna be Full HD, but depending on how it’s transmitted, it might mean there’ll be black to the right and left for example. In order to understand this consider differentiating between the medium and the content. The medium is Full HD (assume an A4 format piece of paper), but the content is in 1.33:1 (a square painted on it). The square wont change the fact that it needs to be shown on an A4 paper, because the standard defines it as such. Not sure if I am explaining it right.