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.

Catherine is one of the oldest and most consistently well-used girls’ names, with endless variations and nicknames. The Catherine form feels more gently old-fashioned and feminine than the more popular K versions. Most stylish nickname for Catherine right now: Kate...or Cate, a la Blanchett.

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.

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.

Sweet and sunny but substantial too, Callie is a nickname-style choice that has long been used as a stand-alone option . Traditionally a diminutive of classic Caroline, it may also be used for Calliope, Camila, Callista, Calanthe, and beyond.

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."

Strong and modern, Cade shot up the popularity lists around the millennium—it was as high as Number 201 in 2001. Now, it has declined in popularity slightly, but nevertheless remains in the US Top 300, given to around 1200 babies each year. Combined with all the baby Kades, Cadens, Kaidens and Kaydens however, it might feel even more popular that it actually is.

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.

Friendly mega-popular short form of Katherine that has definitively replaced Kathy, Katie is often given on its own. Going forward, though, Katie is more stylishly clipped itself to the grownup Kate.

This endearing nickname name is one Katherine pet form that predates all the Kathys and Katies, having been fairly common in the eighteenth century. With the current mini-craze for animal-related names, Kitty is sounding cute and cuddly again—she's already jumped back onto the U.K. list, at number 199.

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."

Popular pop name, inspired by Australian singer Kylie Minogue. It was at its height in Australia in the 1970s and early 80s; often cited as a Noongar name meaning "boomerang".

Kiki is one of the Coco-Gigi-Fifi-Lulu bohemian-type French nickname names from the turn of the last century, which have endless energy and sparkle. Artist Kiki Smith is its most well-known contemporary representative, and Kiki was the inspiring heroine of Zadie Smith's On Beauty. Kiki can be a nickname for any name beginning with the K sound, from Katherine to Christina to Kayla.

This appealing multi-cultural name, pronounced KYE, is beginning to be used for girls as well as boys. Among its many derivations and meanings: "sea" in Hawaiian, "forgiveness" in Japanese, "willow tree" in Navajo, "food" in Maori, and "earth" in Scandinavian. For girls, it debuted on the US Top 1000 in 2010.

Biblical name Cain was, until recently, seldom heard outside of the Old Testament and soap operas. Although Cain's murderous actions will always make this name difficult for some, Cain, Eve and Adam's firstborn, was a farmer - making this a good choice for those with farming connections. Long outshone by Abel, Cain is starting to find a broader audience, helped along by homophones Kane or Caine.

Caden is a key member of the rhyming contingent that includes Aiden, Jayden, Kayden, Brayden et al. It may derive from the Celtic Cadan or Irish Cathán, both from the same root meaning "battle". It is also possible it comes from Cade, meaning "round" or "barrel".

Kali is a number of different things: a playful, contemporary twist on the name Callie; the Hindu goddess of destruction; an alternative spelling for Kaylee; a short form of the Arablic Kalila, the Greek Kalista, or the African American Kaliyah; a masculine name in India; and a trendy form of Kali(fornia).

Although the Kathryn spelling feels like a modern streamlining of this ancient royal and saints' name, it is in fact found back through history. At least one of Henry the Eighth's unfortunately wives sometimes spelled her name as Kathryn.

This member of the aden/ayden extended family is a popular choice not only in the US but across the pond in England, Wales and Scotland as well. Angie Everhart has a son named Kayden Bobby.

Kade falls into the trend of using a letter K at the beginning of a traditionally C-starting name, perhaps to give it a sharper edge. Trending since the 90s, Kade is currently in the Top 400, while Cade ranks nearly around 70 places ahead. Given to 933 babies in 2023, it is a consistently used name.