The phrase "first major" refers to the initial or most important achievement or event in a particular area or field. It signifies the beginning of someone's noteworthy accomplishments or a significant milestone in their journey. Full definition
This was the artist's first major museum survey. (davidzwirner.com)
This exhibition of thirty - one paintings is the artist's first major retrospective; it includes many new, never before seen works. (fineartconnoisseur.com)
Battlefield 1's first major update arrived earlier this week, tweaking various maps, adding hardcore servers and balancing some of the game's weapons. (techtimes.com)