In all these examples we've used a string to name the metric. The metrics library actually names metrics with three-part names. In Java and Scala those names are usually the package and class where the timer is being used.
In Clojure you usually won't have a meaningful class name to record, and the package name would be a pain to find, so metrics-clojure uses "default" and "default" for those parts. This results in a name like "default.default.my-metric".
If you want to specify something other than "default" you can pass a collection of three strings instead of a single string:
(use '[metrics.timers :only (timer)]) (def response-time (timer ["webservice" "views" "response-time"]))
This will result in a name like "webservice.views.response-time".