I have two words I need to know the definition of that are not in my book: disjunction and conjunction. Does anyone know the definitions?

That is mathematical logic talk

conjunction is logical "and"
disjunction is logical "or"

"and" is unambiguous English and
[ intersection of sets ]

"or" means either, or both
For example if I say A or B is true, then only A could be true or only B could be true or both could be true.
[ union of sets]