Sentence:  Jim Landis ' 380 - foot home run over left in the <WSD>first</WSD> inning gave the Sox a 1 - 0 lead , but Harmon Killebrew came back in the bottom of the first with his second homer in two days with the walking Bob Allison aboard . 
Meaning of the word marked with <WSD> tags:  indicating the beginning unit in a series