If you’ve noticed a lot of babies with history-evoking names like Eleanor, Theodore and Evelyn lately, it’s not a coincidence. Baby naming experts actually have a theory for why certain names fall out of fashion, disappear for long stretches of time and then come roaring back. It’s called the “100 Year Rule,” and the framework not only explains current naming trends but may help predict which names will become popular in the coming years.“The 100 Year Rule holds that the style cycle of a name is about 100 years,” Sophie Kihm, editor-in-chief of the baby name resource Nameberry, told HuffPost. “In general, new parents do not want to give their children names that sound dated. These include names strongly tied to their parents’ generation ― today those would be 1960/70s names like Lisa, Susan, Jennifer, Jeffrey, Kevin and Brian ― and their grandparents’ generation, 1940s names like Linda, Barbara, and Sharon, Ronald, Larry and Gary.”The reason these names feel off comes down to simple familiarity.“Parents are likely to know many people with these dated names, all in a certain age range,” Kihm said. “If you ask someone to picture a person named Patricia or Carol or Dennis, they are likely to imagine someone older, perhaps based on people they know with these names.”By contrast, many parents are drawn to names that were peaking about a century ago, a time period most of them have no personal connection to.“Names that peaked 100 years ago belonged to this generation of parents’ great-grandparents,” Kihm explained. “There was not much overlap between these generations, so the younger generation did not have as much exposure to the older generation’s names. Current parents mostly lack elderly associations with names that peaked in the 1920s like Evelyn and Arthur and Marjorie.”In other words, a name that peaked 100 years ago might not register as a particularly dated name to today’s parents because they didn’t know a lot of people with that name of a certain age. Their own parents, however, might feel differently.“Meanwhile, if you ask their parents, they are likely to decry these choices as ‘old people names’ since those were the names of their grandparents, of whom they have memories,” Kihm said.enigma_images via Getty ImagesNameberry's "100 Year Rule" is simple but telling. Nameberry’s co-creators, Linda Rosenkrantz and Pamela Redmond, identified the trend and coined the term in their 1988 book “Beyond Jennifer & Jason.”“When they compiled their historical data, they realized that many of the names popular in the 1880s and 1890s sounded fresh and were rising in popularity in the late 1980s,” Kihm said. “Thus, the 100 Year Rule was born.”This rule doesn’t simply come down to aesthetic preference.“There is a cultural desire to give children names that are congruent with their generation,” Kihm said. “Psychologically, this may be related to the general distaste of things that are ‘old.’ Parents are drawn to names that feel fresh. These include names that are newer to the lexicon ― Nova, Maverick, Wrenley ― and names that haven’t been trendy in about 100 years.”There’s also a practical appeal for families who want to honor their history.“Expectant parents may like names that fit the 100 Year Rule because they are traditional, time-honored choices that feel exciting and often unique. For some parents, it is a way to use family names that still give their child their own identity, since the child might be the only living bearer of that name,” Kihm noted. She gave Eloise and Eleanor as examples of names currently in their 100-year window and listed other picks that are trending up as well: Marjorie, Winona, June, Maxine, Ramona, Dorothy, Warren, Leon and Wallace.“Names that are entering their window and expected to gain popularity include Althea, Marcella, Betty, Blossom, Lois, Howard and Murray,” Kihm noted. “These haven’t ‘popped’ yet but they will soon.”Of course, not every name perfectly follows Nameberry’s 100-year timeline. Kihm pointed to names that are already trending again like Rosemary (which peaked in 1946), Penny (peaked in 1964), Dean (peaked in 1968), Waylon (peaked in 1980), Wyatt (peaked in 1957) and Margot (whose homonym Margo peaked in 1951). There are also those that resist revival entirely. “Names that are stubbornly refusing to return are Edna, Nettie, Arnold, Sylvester, Rufus, Mildred and Millicent ― which is surprising given the popularity of Millie,” Kihm said. And then there are the true classics ― names that exist essentially outside the rule altogether.“Truly classic names defy the 100 Year Rule,” Kihm said. “Particularly the classic boy names because they have been in constant use for centuries. The ultra-classics like Elizabeth, Rose, William, Henry and John still go through popularity cycles, but they don’t dip as low and reverse course much sooner than non-classics.”