This spirited Gaelic classic, which became popular in Ireland via the illustrious twelfth century king Rory O'Connor, makes a highly energetic choice, now used for either sex. Rory's gender split is still trending boyward; it's one of the coolest boys' names starting with R.

Celebrated in song—the rock 'n' roll classic "Louie, Louie"—this is a gregarious, friendly spelling of Louis not often used as a full first name. It reentered the US Top 1000 in 2015. It's a highly popular choice in England and Wales.

Sam has long been used on its own for boys, as accepted standing by itself as it is as a short form of Samuel. Straightforward and down-to-earth, Sam is the name of the son of the co-stars of The Americans, Keri Russell and Matthew Rhys. Sam is one of the most popular names that start with S in the Western world, ranking higher in several European countries than it does in the US, where it's trended downward since the 19th century, though it's always been in the Top 1000.

Down-home nickname name once associated with the friendly dragon on kids' TV. As Oliver rises, we may well hear more Ollies.

This might sound and look like a blend of Ryan, Riley, and Nigel, but it is in fact the name of the seventh brightest star in the sky. Found in the constellation of Orion, its name comes from the Arabic phrase, Rijl Jauzah al Yusrā, , meaning "the left foot of the central one."