declare namespace request="http://exist-db.org/xquery/request";
declare namespace transform="http://exist-db.org/xquery/transform";

let $word := request:request-parameter("word","")
let $terms := collection('db/ChrisWallace/medical')/terms/term[name &= $word]
let $ss := doc('/db/ChrisWallace/medical/search.xsl')
let $params := 
<parameters>
  <param name="heading" value="Definition of {$word}"/>
  <param name="word" value="{$word}"/>
</parameters>

return
   transform:transform(<Result>{$terms}</Result>,$ss,$params)