Source : Webster's Revised Unabridged Dictionary (1913)

Sidesman \Sides"man\, n.; pl. {Sidesmen}.
   1. A party man; a partisan. --Milton.

   2. An assistant to the churchwarden; a questman.

Source : WordNet®

sidesman
     n : (Church of England) an assistant to the churchwarden;
         collects offerings of money in the church