We're using a couple of different terms for non search referrer traffic
- 'Other' - http://searchdata.wmflabs.org/external/ (Summary)
- 'None' - http://searchdata.wmflabs.org/external/ (Page Views by Search Engine)
and possibly others I haven't tracked down.
Let's standardize. I'd suggest 'Non Search Traffic' to be explicit and clear that it not search related and also not simply unidentifiable. thanks