Astrology
Horoscope
noun
占い is "fortune telling." Star fortune telling is when you use the stars for fortune telling. That's known as astrology or horoscope.
ほしうらない
The reading is the words 星 and 占い put together into one. Did you foresee that one coming?
今日の星占いで、頭にたんこぶができないように気をつけた方がいいと出ていたの。
Today’s horoscope says I should be careful of getting a bump on my head.