Q: What is a word used to describe something that 'wasn't meant to be' I looked up this phrase on Google and got basically no clear results.
What does this phrase mean and which context is it used in?

A: It (just) wasn't meant to be derives from the idiom meant to be, which means "destined to exist" (here).
People say that something (for example, an event) was "meant to be" when they want to attribute that thing to fate or destiny. It is a fatalistic expression.
To say that something (for example, an event) "wasn't meant to be" means that the thing was not destined to happen (or that it was destined to not happen). It attributes the thing's not happening to fate or destiny.
It has roughly the same meaning as the idiom it just wasn't in the cards.
