year of service
(2) (A) For purposes of this section, except as provided in subparagraph (C), the term “year of service” means a calendar year, plan year, or other 12-consecutive month period designated by the plan (and not prohibited under regulations prescribed by the Secretary) during which the participant has completed 1,000 hours of service. (B) For purposes of this section, the term “hour of service” has the meaning provided by section 1052(a)(3)(C) of this title . (C) In the case of any seasonal industry where the customary period of employment is less than 1,000 hours during a calendar year, the term “year of service” shall be such period as determined under regulations of the Secretary. (D) For purposes of this section, in the case of any maritime industry, 125 days of service shall be treated as 1,000 hours of service. The Secretary may prescribe regulations to carry out the purposes of this subparagraph.