Ms. Rockwell compiled spreadsheets filled with notations on government trend data (“Olivia,” an early favorite, was spiking ominously, she found), tabloid favorites (“Penelope” was rejected when Kourtney Kardashian claimed it); and cultural nuances (was it good that “Rosamund” evolved from “horse protector” in German?). She and her husband eventually settled on “Imogen,” a name with pleasing literary overtones (Shakespeare’s “Cymbeline”): distinctive, but not weird, they thought.

Not long ago, unusual baby names were largely the province of celebrities — who can forget the rolled eyes that greeted “Apple” (Gwyneth Paltrow and Chris Martin’s daughter) or “Moxie CrimeFighter” (Penn Jillette’s daughter).

Now, ordinary mortals are getting into the act. The Social Security Administration’s list of the most popular baby names in the United States for 2012, released last month, showed a continued slide for staples like “John” (now No. 28) and “Mary” (123), which were among the Top 5 for a big chunk of the 20th century; the biggest gainers were “Major” (483 from 988) and “Arya” (413 from 711).

“Finding a name that has authentic roots, but is completely undiscovered, is the ultimate baby name status symbol,” said Pamela Redmond Satran, a founder of the site Nameberry and an author of a new e-book called “The Nameberry Guide to Off-the-Grid Baby Names.” Even when parents look to the Bible, they often thumb past “Adam” and “Daniel” in favor of “Joah” or “Obadiah,” she said.

In 2002, 77 percent of babies born in the United States had names on the Top 1000, according to government data. By 2011, only 73 percent did. Keep in mind that “Maxton,” “Krish” and “Brecken” already were on the Top 1000. To get more obscure than those, you basically have to draw Scrabble tiles randomly, which is perhaps how parents come up with neologisms like “Cree,” “Izan” and “Emi” (for boys) and “Safi,” “Nanou” and “Esosa” (for girls), all of which cropped up for the first time last year among the 450,000 births to registered users of BabyCenter.