The first time a star is mentioned in the Bible, and most of the mentioning afterwards, is in its plural form: ko•cha•vim.
“And God made two great lights; the large light to rule the day, and the small light to rule the night; and he made the stars”
In all the rest of the 35 times the word appears in the Old Testament it appears either in plural or in a conjugated form, except for two times when it is called Ko•chav. In both of these cases the reference is not to an actual star but rather it is using a figurative language:
“…there shall come a star out of Jacob”
“…and Kiyun, your images, your star-god, which you made for yourselves”
In the New Testament, on the other hand, the singular word ko•chav appears 10 times. It is always a reference to an actual star. For example:
“and I will give him the morning star”