No, they’d still be considered row houses according to the ‘rules’ - to be semi-detached, you must be one half of a pair.
The reason for the terminology is mostly social - a semi detached house is much more middle class than a row house, much more desirable.
There are also, often, important legal differences. Semi-detached homes generally have a separate title for each of the homes and the land they sit on, where row houses generally only have one title for the whole row. You can buy a single semi-detached house, you can’t generally buy a single row house.
A duplex, by the way, in the UK (and Australia) is when you have a two floor building with a separate ‘house’ on each floor.
OK, thanks for the info.