Mass. Gen. Laws ch. 184B § 1
The terms defined in this chapter may be used in any will or trust and, except as otherwise provided in the instrument, shall have the full force, meaning and effect of the words by which they are so defined. Adoption or employment in substance of a defined term in such instrument shall be a sufficient incorporation by reference of the applicable section of this chapter in effect at the date of the execution of the instrument, but this provision shall not preclude other methods or incorporation of any section in part only or subject to such modification as the incorporating instrument may provide. An attorney at law preparing a will or trust who uses a term defined in this chapter shall furnish to the testator or settlor a copy of the section of this chapter by which the term is defined; provided, however, that failure to do so shall not affect the validity of the incorporation by reference.
Mass. Gen. Laws ch. 184B, § 1