(1) As used in this section the following words and phrases shall, unless the context clearly requires otherwise, have the following meanings:—

1. (a) ''Extended benefit period'', a period which begins with the third week after a week for which there is a state ''on'' indicator; and which ends with either of the following weeks, whichever occurs later;

2. (i) the third week after the first week for which there is a state ''off'' indicator, or (ii) the thirteenth consecutive week of such period; provided that no extended benefit period may begin by reason of a state ''on'' indicator before the fourteenth week following the end of a prior extended benefit period which was in effect with respect to the commonwealth.

   [There is no paragraph (b).]