This is the 194th most frequent German word.
daher
"Therefore" or "thus."
In this sentence, 'daher' indicates a causal relation, meaning 'therefore'.
Ich habe dein Problem verstanden, daher helfe ich dir.
I understood your problem, therefore I am helping you.
Here, 'daher' refers to a spatial source meaning 'from there'.
Daher kommt der merkwürdige Geruch.
That's where the strange smell comes from.
In this sentence, 'daher' is used to convey a conclusion, equivalent to 'so' or 'therefore'.