If you are travelling forwards and a wind is blowing against you, coming from the opposite direction, it is a "headwind". This kind of wind slows you down. The opposite kind of wind which comes from behind you and is blowing in the direction of travel, is a "tailwind". This kind of wind speeds you up. Winds coming from the left or right as you are travelling are called "crosswinds". I hope this answers your question. Kind regards, Michael