Current translation for Westham
  west derived from wæst  – west
  ham derived from hamm  – Denotes a piece of land surrounded with paling, wicker-work, etc., and so defended against water, which would otherwise wash it away, so a valley settlement or settlement with a jetty.
“West denotes a piece of land surrounded with paling, wicker”
Place name translation provided by saxonhistory.co.uk