tertiary
College is considered post-secondary education.
Post secondary education is the educational level following the completion of a school providing a secondary education. This would include high school (secondary school). Thus, any degree in higher education following secondary school is considered post secondary, if not then it is not post secondary.
the teenage years, teenagers, secondary-school-aged, pubescence or post-puberty,
I have attended two post-secondary schools.
when you learn about post
In this case, post is a prefix, not a standalone word. Therefore, it should be properly hyphenated as post-secondary.
pole, post, spar
secondary, additional, extra, subsidary, supplementary
Yes, college is considered a form of post-secondary education.
office is like a post or a business
post, following
Yes it is. If a school is a college or university, it is a post secondary institution.