It is two words. Writing it as one is acceptable in the UK and is referred to as a "Britishism." But in American grammar, it is always two separate words.
Two words - "one day".
They are two words conjoined to be one.
The key components of a bodyweight workout are described in the following sites for you to look at. www.fitday.com/fitness.../an-introduction-to-bodyweights.html , and www.realbuzz.com/articles/using-your-own-bodyweight-to-exercise/
"After school" is typically written as two words.
It is two words take it from a 7th grader
The term "in touch" is considered to be two words.
I recommend class work, as two words.
It is two words.
Two words.
It is two words.
Two words.