A friendly Irish and Persian name chosen by Geena Davis for one of her twin boys, whose father is Iranian.

Kai is an internationally flexible name with many possible origins and meanings, growing in popularity in the US and a diverse range of European countries.

Long popular in Ireland and England, Kieran, the name of Ireland's first-born saint and twenty-five other saints, has been building its U.S. fan base thanks to its strong and attractive sound, and its fashionable Irish brogue. While Ciaran is the more authentic Irish spelling, Kieran is more popular this side of the Atlantic.

Kevin came to the US with the large wave of Irish Immigrants after World War I, hitting the US Top 1000 list for the first time in 1921 and never leaving.

Katherine is one of the oldest, most diverse, and all-around best names: it's powerful, feminine, royal, saintly, classic, popular, and adaptable. Long one of the top girls' names starting with K, Katherine has now been unseated on the popularity list by upstarts Kennedy and Kinsley, but a dip in popularity only adds to its charm.

The new Maia, the next Kayla, Kaia has been on the charts since the year 2000. You might see it as a female form of the also-rising Kai, which means sea in Hawaiian and is sometimes used for girls as well, or as a Kardashianization of the ancient goddess name Caia.

Kenneth may have lost much of its luster now, but Kenneth has had its moments of glory. The first king of Scotland was Kenneth, and Sir Kenneth, a Christian crusader, was the hero of the Sir Walter Scott novel The Talisman.

Kiara can be considered a variation of both the Italian name Chiara and the Irish name Ciara. Chiara is the Italian form of Clara, meaning "bright" or "clear," while Ciara is the feminine form of male given name Ciar, derived from the old Irish cíar, meaning "dark."

Though such cognates of Kira as Keira, Kyra, and Ciara are increasingly popular throughout Europe and in the U.S., this Cyrus relative has a different root. As with all the many variations of this appealing name, there is often confusion around spelling and pronunciation -- does the first syllable rhyme with ear or eye?

Knox is an old Scottish surname that Brad Pitt (whose great-great-grandfather was named Hal Knox Hillhouse) and Angelina Jolie took out of the back cupboard, dusted off, and elevated to coolness--to the point where it entered the popular baby names list in 2009. Knox now ranks among the most influential celebrity baby names.

Keira is an attractive girls’ name that's gotten a huge boost from the meteoric rise of Keira Knightley. Original spelling Kiera, which relates more directly to the male Kieran, was the more popular form until the rise of Keira Knightley reversed the order. Both are Anglicized versions of the Irish Ciara.

Kayla is a modern invented name that emerged in the late 1950s. It may have been inspired by the similar sounding Michaela, though it could equally have come about as a combination of the then popular name popular name Kay and the familiar -la suffix.

A name of multiple identities: a somewhat soap-operatic single-syllable surname, a homonym for the biblical bad boy Cain, and, when found in Japan and Hawaii, it transforms into the two syllable KA-neh. Kane also has multiple meanings: in Welsh, it's "beautiful"; in Japanese, "golden"; and in Hawaiian, "man of the Eastern sky."

Kate, in the headlines via Catherine Middleton aka the Princess of Wales, has been as pervasive as Kathy was in the 1950s and 1960s, both as a nickname for Katherine and Kaitlyn and as a strong, classic stand-alone name.

Strong but gentle, Keith is one of the Scottish surnames that, along with Douglas, Craig and Bruce, were considered the epitome of cool in the 1960s and early 1970s, when it was a Top 40 choice.

Karen, a once sweet Danish import, was so popular during the baby boom (Karen was Number 3 in 1960) that it's become a mem in recent years, representing a hostile white woman—one who usually wants to speak with the manager.

Kimberly's heyday was in the 1960s and 70s, when it ranked among the Top 10. While it hasn't been stylish for decades, it's evidenced more staying power than some former hot girl names, remaining among the Top 300 girl names in the US, where it's stood for 70 years.

Kathleen is the early Irish import version that came between Katherine and Kaitlin, and which hasn't been used in so long it's almost beginning to sound fresh again. It was a surprise pick by one of the hip Dixie Chicks, Martie Maguire. Kathleen was a Top 10 name from 1948 to 1951, and it is the subject of several old sentimental songs, such as "I'll Take You Home Again, Kathleen."

Kiera entered the American popularity list in 1988, though it lags behind the alternate spelling Keira, largely due to the fame of actress Keira Knightley.

Kendra was once seen as a feminization of Kenneth -- but it's now firmly established as a standalone. American parents can't seem to make up their mind about it though: it was one of 2013's fastest-rising names, entering the Top 200 for the first time since 2000, but then it tumbled again.