This page tells you about the types of searches you can have in dashboards. https://docs.splunk.com/Documentation/Splunk/8.1.3/Viz/Savedsearches but basically a base search is something that you can use as a building block for other searches, e.g. <search id="this_is_a_base_search> <query> index=_internal | stats count by user </query> </search> and then you can have other searches that build in that, e.g. you could have a single panel showing a count for two users that uses that base search, such as <single> <search base="this_is_a_base_search"> <query> | where user="admin" </query> </search> </single> and <single> <search base="this_is_a_base_search"> <query> | where user="Dheeru" </query> </search> </single>  they would use the results from the first search. You can also have multiple levels of base search, so a search can be also a base search but use another base search, e.g. from the above search, it could be... <single> <search id="i_am_a_new_base_search" base="this_is_a_base_search"> <query> | where user="Dheeru" </query> </search> </single>   ... View more