This is the 7759th most frequent Spanish word.
lunin
It seems "lunin" is not a standard Spanish word. It may be a typo or a regional/local term.
In this sentence, 'lunín' is used poetically to refer to a celestial object or light source, possibly resembling the moon or its glow.
El lunín brilla en el cielo nocturno.
The lunín shines in the night sky.
Here, 'lunín' might refer colloquially or affectionately to a small light or lamp used outdoors at night.
Mi abuela tenía un lunín en su jardín que iluminaba las noches.
My grandmother had a lunín in her garden that illuminated the nights.
In this instance, 'Lunín' is a proper noun, a fictional name given to a character in a story, derived from 'luna' or the concept of light and celestial figures.