This is the 2067th most frequent Polish word.
miliardy
"Billions."
Here, the word "miliardy" is used to denote a numerical quantity.
Na świecie żyją miliardy ludzi.
Billions of people live on Earth.
In this sentence, "miliardów" appears in the genitive plural form to quantify 'years' in temporal context.
Już od miliardów lat planety krążą wokół Słońca.
For billions of years, planets have been orbiting the Sun.
This usage of "miliardy" signifies a large count of 'stars' visible in the context of the sky.