According to wikipedia:

Labor Day is a federal holiday in the United States celebrated on the first Monday in September to honor and recognize the American labor movement and the works and contributions of laborers to the development and achievements of the United States.

と、wikipediaにあります。日本で言う、勤労感謝の日、のようです。

Etymology, 語源、を紹介するサイト、etymonline.comによると、

labor (n.)

c. 1300, “a task, a project” (such as the labors of Hercules); later “exertion of the body; trouble, difficulty, hardship” (late 14c.), from Old French labor “toil, work, exertion, task; tribulation, suffering” (12c., Modern French labeur), from Latin labor “toil, exertion; hardship, pain, fatigue; a work, a product of labor,” a word of uncertain origin. Some sources venture that it could be related to labere “to totter” on the notion of “tottering under a burden,” but de Vaan finds this unconvincing. The native word is work.

語源は不確かなようです。反論は予想できるが、「重荷を背負ってよろよろ歩くこと」、とも言っています。

ヘラクレスの仕事について、wikipediaはこう言っています。

The Labours of Hercules (Greek: οἱἩρακλέουςἆθλοι, hoì Hērakléous âthloi)^[1][2] are a series of episodes concerning a penance carried out by Heracles, the greatest of the Greek heroes, whose name was later romanised as Hercules.