If an instruction omits a required definition of an offence is harmless only if the error is proven beyond a reasonable doubt, can the error be reversed?

Alternatively, where an instruction omits a required definition, we apply the standard set forth in Chapman v. California (1967) 386 U.S. 18. Under that standard, "An instruction that omits a required definition of or misdescribes an element of an offense is harmless only if 'it appears "beyond a reasonable doubt that the error complained of did not contribute to the verdict obtained." ' " (People v. Mayfield (1997)

Page 12

14 Cal.4th 668, 774, overruled on other grounds in People v. Scott (2015) 61 Cal.4th 363, 390, fn. 2; People v. Harris (1994) 9 Cal.4th 407, 424.) As defendant correctly asserts, the trial court's error warrants reversal under either standard.