The Splunk Interface - Implementing Splunk: Big Data Reporting and Development for Operational Intelligence - page 10

A host is a captured hostname for an event. In majority of the cases, the host field is
set to the name of the machine where the data originated. There are cases where this
is not known, so the host can also be configured arbitrarily.
Search
We've finally made it to search. This is where the real power of Splunk lies.
For our first search, we will search for the word error . Click in the search bar, type
the word error , and then either press Enter or click on the magnifying glass on the
right of the bar.
Upon initiating the search, we are taken to the search results page.