Del. Code tit. 30, § 1101

Any term used in this chapter shall have the same meaning as when used in a comparable context in the laws of the United States referring to federal income taxes, unless a different meaning is clearly required. Any reference to the laws of the United States shall mean the Internal Revenue Code of 1986 [26 U.S.C. § 1 et seq.] and amendments thereto and other laws of the United States relating to federal income taxes, as the same may have been or shall become effective, for any taxable year.