registration period

For purposes of this section, the term “registration period” has the meaning given such term under section 1 of the Railroad Unemployment Insurance Act (45 U.S.C. 351).

The term “registration period” means also, with respect to any employee, the period which begins with the first day with respect to which a statement of sickness for a “period of continuing sickness” (as defined in section 352(a) of this title) is filed in his behalf in accordance with such regulations as the Board may prescribe, or the first such day after the end of a registration period which will have begun with a day with respect to which a statement of sickness for a “period of continuing sickness” (as defined in section 352(a) of this title) was filed in his behalf, and ends with whichever is the earlier of (i) the thirteenth day thereafter, or (ii) the day immediately preceding the day with respect to which a statement of sickness for a new “period of continuing sickness” (as defined in section 352(a) of this title) is filed in his behalf.