This was too long for a comment, so I wrote an answer. I did not add this to my first answer because a lot of people already upvoted my first vanswer and I am not sure they agree with this answer, too.
- I don't think that linearithmic is a well established term as stated in a comment to the accepted answer.
I googled some rather young articles using this term, a CS course and another book by Sedgewick that uses this term and a lot of online dictionaries.
- The term quasilinear I found in two articles:
Satisfiability Is Quasilinear Complete in NQL
C. P. Schnorr
Journal of the Association for Computing Machinery,
Vol 25. No 1, January 1978, pp 136-1,15
and in an article cited in the Wikipedia that deals with this Schorr's article. Schnorr introduces the complexity classes quasilinear (QL) and nondeterministic quasilinear (NQL).
Quasilinear seems to be used in the theory of partial differential equations, too.
All in all it seems that one or more Wikipedians wanted to supply names for this function that does not have a widely accepted name. But even now it seems to me that none of the names is widely accepted (besides that I think this is a kind of manipulation that Wikipedia should not do). I think one has to be cautious if one uses Wikipedia for terminology questions. And for this function it is not a sufficient source. I think the only widely accepted name for this function is n log n.