Sentence:  Thru May: 1920s — The <WSD>Decade</WSD> That Roared. New exhibition portraying historical events and everyday life during the Roaring Twenties. 
Meaning of the word marked with <WSD> tags:  A period of ten years (from 17th c.), particularly such a period beginning with a year ending in 0 and ending with a year ending in 9. (from 19th c.)