• (n.) A person dispatched before another person or company, to give notice of his or their approach.
A·vant'-cou`ri·er noun [ French, from avant before + courrier . See Avaunt , and Courier .] A person dispatched before another person or company, to give notice of his or their approach. 
A French word meaning 'scout'. This word was used by both voyageurs and mountain men.