[DOCS] Add 'search template' glossary definition (elastic#1723)

Author: jrodewig

docs/en/glossary/glossary.asciidoc

@@ -1069,6 +1069,11 @@ include::{kib-repo-dir}/glossary.asciidoc[tag=scripted-field-def]
 include::{kib-repo-dir}/glossary.asciidoc[tag=search-session-def]
 --
 
+[[glossary-search-template]] search template::
+A stored search you can run with different variables. See
+{ref}/search-template.html[Search templates].
+//Source: Elasticsearch
+
 [[glossary-searchable-snapshot]] searchable snapshot::
 <<glossary-snapshot,Snapshot>> of an <<glossary-index,index>> mounted as a
 <<glossary-searchable-snapshot-index,searchable snapshot index>>. You can search