John the Baptist went before our Lord in this character (Mark 1:2, 3). Christ so called (Hebrews 6:20) as entering before his people into the holy place as their head and guide.

Noah Webster's New International Dictionary of the English Language

1. (n.) A messenger sent before to give notice of the approach of others; a harbinger; a sign foreshowing something; a prognostic; as, the forerunner of a fever.

2. (n.) A predecessor; an ancestor.

3. (n.) A piece of rag terminating the log line.