The California Revised Uniform Limited Liability Company Act defines "person" to mean, among other things a "trust, a trustee of a trust, including, but not limited to, a trust described under Division 9 (commencing with Section 15000) of the Probate Code".  Cal. Corp. Code § 17701.02(v).   Because I do not practice in the area of trust law, I had to look up what Division 9 of the Probate Code is all about.  It turns out that this division is known, and may be cited, as the "Trust Law".  Cal. Prob. Code § 15000. 

What is a trust described "described under Division 9 (commencing with Section 15000) of the Probate Code?  Much to my surprise, it turns out that all trusts are subject to Division 9.  Cal. Prob. Code § 15001(a) ("This division applies to all trusts regardless of whether they were created before, on, or after July 1, 1987.").

Putting Corporations Code Section 17701.02(v) and Probate Code Section 15001(a) results in the following definition: 

"'person' means . . .  trust, a trustee of a trust, including, but not limited to, all trusts . . . ."

With apologies to A.E. Houseman, this trust as a person business "gives the chap a belly-ache".