Steeping (to steep) is a culinary term that refers to the soaking of an ingredient in water to extract the flavor of the ingredient. One "steeps" tea leaves in hot water to infuse the water flavor of the tea. Similarly you steep flower blossoms such as jamaica in hot water to make agua de jamaica, a type of agua fresca.
Hot water is not always used to steep tea or other herbs. Cold water can be used too but it will take longer to extract the flavor. For example to make iced tea using cold water the process will take about 6 - 8 hours rather than just a few minutes.