This is the 18002nd most frequent Polish word.
świeciła
"Świeciła" means "shone" or "was shining" in English.
The word 'świeciła' is a form of the verb 'świecić' in past tense, feminine singular, describing an action performed by the moon.
W nocy księżyc świeciła jasno.
At night, the moon shone brightly.
Here 'świeciła' as past feminine is used figuratively for an inanimate subject—the lightbulb.
Żarówka w pokoju przez chwilę świeciła, zanim się przepaliła.
The lightbulb in the room shone briefly before it burned out.
In this context, 'świeciła' graphically describes the light-emitting property of the star on the tree, in past tense.