Throughout history, Pugs have been called by many names.  In China, Pug-type dogs with short coats and wrinkled foreheads were known as Lo-Sze, and it was probably these dogs that gave rise to the Pug we now today.

Because of its body contour, wrinkled head and associated with Holland, the early Pug of Europe was known as the Dutch mastiff, or sometimes the dwarf mastiff.  In the early 18th century, the breed was sometimes called the Dutch Pug.

Popular pets of the 17th and 18th centuries included not only the little Oriental dogs but also marmoset monkeys.  The two animals bore a resemblance to each other, and the monkeys, which were known as pugs, may have given their name to the dog breed.  The word "pugg" or "pugge" was also used as a term of endearment during this time.

The dog authority Stonehenge suggested that the breed name came from the Latin word pugnus, meaning "fist," because the shadow of a clenched fist was considered to resemble the dog's profile.  To think that the breed is pugnacious, however, would be a mistake.  The Pug is more of a lover than a fighter.

Over the years, the Pug has carried a number of nicknames.  In Holland, it's often known as the mopshond, from the Dutch word meaning "to grumble," a reference to its frowny face.  The Germans call it mops, as well.  Because of their black facial masks, French Pugs were called carlins, a reference perhaps to an 18th-century French actor known for h is role of Harlequin.  In this country, members of the breed are affectionately known as Puggies, Pugglies, and Puglets.  

-Kim Campbell Thornton
Pugs 
All About America's Favorite Dog Volume 23