Macy's, Inc. (NYSE:M) has its sights set on Millennials, the generation of Americans roughly defined as those born in the waning years of the 20th century. (More about that below.)

The company said Thursday it will roll out 13 new brands and expand 11 others, including women and girls’ apparel and shoes inspired by Marilyn Munroe, a persistent favorite among consumers even 50 years after the model, actress and singer’s death. The chain will also introduce in-store units in a tie-in with fashion-oriented Milk Group’s MADE Fashion Week. The Cinncinnati-based retailer has divided the male and female Millennial shopper into two age groups: 13-to-22 under the chain’s current "mystylelab" department and 19-to-30 in its "Impulse" department.

“We have identified Millennials as a priority customer for Macy’s,” Jeffrey Gennette, Macy’s chief merchandising officer, said in the company’s announcement Thursday.

Millenials are estimated to spend $65 billion annually on the type of merchandise stocked by Macy’s. The oldest of the Millennials recently turned 30 and they’re shifting from being newbies to higher paid, more experienced employees. Efforts by Macy’s to attract the next generation of big spenders are happening as Baby Boomers, those born from 1945 to 1965, are shifting to jobless pensioners. Generation Xers, the children of the Boomers born in the late 60s and 70s, are in the midst of their peak income-earning years.

There are many ways Millenials are characterized by market researchers. Millenials are generally considered more optimistic than their predecessors, the ones born early enough to have experience the perpetual threat of Cold War nuclear annihilation and the disquieting policy of Mutual Assured Destruction.

Millennials tend to read more than Generation X — albeit probably online or from a tablet. They’re (arguably) less concerned about the environment. They’re more racially diverse and politically active than the previous generation, but their preferences have racial undertones; younger Millennial whites strongly favor Mitt Romney while non-whites overwhelmingly support Barack Obama. As the first generation to come to age with the internet, they are more comfortable with new technologies and e-commerce, much to the concern of traditioanal brick-and-mortar stores.

Generation Xers, and increasingly Millennials, also have more of an influence over how their retiring parents spend money, especially when it comes to electronics -- a classic example being parents who ask their children advice on what kind of computer or smart phone to buy, and then how to use that item once the purchase is made. Studies suggest Millennials' relationship with their parents are better than with preceding generations.

"Millennials get along extraordinarily well with their parents," Morley Winograd, a senior fellow at the University of Southern California's Annenberg Center on Communication Leadership and Policy and co-author of "Millennial Momentum"  told "Half of them talk to their mother every day, even if only by text. As a result, they have enormous influence on family purchasing decisions, especially for technology, cars, and other durable goods."

Historians Neil Howe and William Strauss define Millennials as members of the generation in the United States born in or after 1982. The oldest Millennials were in diapers during the early years of U.S. President Ronald Reagan. Many at the trailing end were sitting in high school classrooms during the terrorist attacks of Sept. 11, 2001, which was the year they first outnumbered Baby Boomers, according to U.S. Census numbers,  including the people born in the U.S. that year.

No clear ending date distinguishes Millenials from more recently born Americans -- including many born to Millennials themselves. Figures vary. Some use birth years between 1980 and 1995; others say 1978 to 2000.

Any specific timeframe would be a rough definition at best since societal shifts happen in a continuous rather than incremental fashion. Howe and Strauss – who specialize in generational theories -- champion 20 years as the time it takes for values (including spending habits and consumer preferences) to exhibit some characteristics that are distinct from those of the preceding generation.

Using the 1982 starting date and the 20-year timeframe, the Millennial generation ended in 2002. This means that the senior class of the next social generation is currently in elementary school. How those future earners choose to spend their money would be as speculative as trying to image what a Macy’s showroom will look like in 2022.

Last month Macy’s reported a wider loss in its second quarter on weaker same-store sales. Shares in the company were trading down 0.71 percent to $40.55 on Thursday. The company’s stock has gained $7.85 so far this year, or 24 percent.