Sentence:  Every body knows what an important epoch <WSD>"Mardi Gras</WSD>" forms in the annual enjoyments of the French. It is the last day of the carnival gaieties, and that which precedes the gloominess of Lent. 
Meaning of the word marked with <WSD> tags:  The last day of a carnival, traditionally the celebration immediately before the start of Lent when joy would be out of place for Christians.