Is extrinsic evidence allowed to prove the meaning of terms in a will?
If there is no ambiguity, extrinsic evidence is not allowed.
If there is a latent ambiguity (i.e. facts and circumstances outside the will establish that an ambiguity exists), then extrinsic evidence is allowed. Ex: I give $10,000 to my nephew John Paul Jones. T has 2 nephews – James Peter Jones and Harold Paul Jones, who takes?
If there is a patent ambiguity (i.e. ambiguity on the face of the will), then extrinsic evidence is allowed. Ex: I give my son twenty-five dollars ($25,000).