8 U.S.C. § 1101(a)(33) (2010) (Title 8—Chapter 12: Immigration and Nationality)
(a) As used in this Act—
(33) The term "residence" means the place of general abode; the place of general abode of a person means his principal, actual dwelling place in fact, without regard to intent.
28 CFR § 21.1(e) [28 CFR PART 21—WITNESS FEES]
The term residence is not limited to the legal residence, but includes any place at which the witness is actually residing and at which the subpoena or summons is served. If the residence of the witness at the time of appearance is different from the place of subpoena or summons, the new place of residence shall be considered the witness' residence for computation of the transportation allowance; but, if the witness is on a business or vacation trip at the time of appearance, the witness shall be paid for travel from the place of service if this does not result in the witness being paid for more travel than is actually performed.