I use bathroom/washroom interchangably...with a preference for "bathroom"

Junior high used to exist in parts of Greater Vancouver until the early 90's, and highschool was just grade 11/12. Then they merger junior high and high, so now all high schools are grades 8-12.

In the BC private school system, we refered to primary/elementary school as Junior School and high school as Senior School. Not sure if that is the same for the rest of the country.

Some Ontario private schools do the same. Others have "lower school" for the elementary grades and "upper school" for the senior grades. Many also have a "middle school" which is a division of the senior/upper school (usually grades 7 and 8, though some schools, especially those that start at the higher elementary grades, have middle schools that start as young as Grade 5)

It can vary by county or by state, but here we had elemetary K-5, Middle 6-8 and high school was 9-12