A 3/4 bathroom in a home is similar to a full bathroom but the exception is that the full bathroom has a tub and shower combo or a separate shower stall and bathtub along with the toilet and sink.
When it comes to a 3/4 bathroom the 3/4 bathroom is a bathroom that has the toilet, sink and a shower stall and not a bathtub.
So if you see a home that has a 3/4 bathroom then it means that the bathroom is fitted with a shower stall but not bathtub.
Some homes have an extra bathroom that has just a shower, toilet and sink which is the 3/4 bathroom and then have another bathroom that has the tub and shower combo or a separate shower and tub in the same bathroom along with the toilet and sink.