This is the 9th most frequent Lithuanian word.
nuo
"From" or "off."
In this sentence, 'nuo' is used to indicate a spatial distance from a point (the door).
Aš atsisėdau toliau nuo durų.
I sat further away from the door.
Here, 'nuo' expresses a starting point in time (early morning).
Nuolat dirbdama nuo ankstaus ryto iki vėlaus vakaro, ji visada buvo pavargusi.
Working continuously from early morning till late evening, she was always tired.
In this instance, 'nuo' is employed in an idiomatic expression to convey heartfelt intensity.