Dictionary meaning of Tailwind is a wind blowing from behind i.e. in the direction of forward motion. Similarly the dictionary meaning of Headwind is a wind blowing from directly in front, opposing forward motion.
Tailwinds describes some condition or situation that will help move growth higher. For example, falling gas prices will help a logistics company more profitable. Lower gas prices is said to be a tailwind for the logistics industry. Headwinds are just the opposite. Its a situation what will make growth more difficult.
Tailwind and Headwind implies same meaning in Investing world as well as its dictionary meaning. If the wind is at your back (tailwind), that will help you move forward more quickly. If you are moving into a headwind, that will only make progress more difficult.