Scrumdiddlyumptious, splendiferous and frightsome are among more than 1,000 words that have been added and revised by the Oxford English Dictionary to include references to beloved children’s writer Roald Dahl.

The dictionary decided to revise and add words that are connected with Dahl’s writing in honour of what would be his 100th birthday on Sept. 13. Direct mentions of words in Dahl’s books have now been added to revised words.

In a blog post written by Jonathan Dent, a senior editor for the Oxford English Dictionary, describes the process of developing histories for words associated with the writer. According to Dent, Dahl’s use of words like scrumptious helped to change their meanings.

The blog post found the word dates back to 1823 and originally meant mean or stingy. It was then carried over to the United States by English settlers where the meaning changed to small, fastidious and scrupulous. In the 1900s, Dahl’s use of the word in James and the Giant Peach – “I’ve eaten many strange and scrumptious dishes in my time,” – helped the word come to its current meaning in speech.

Dahl first published The Gremlins in 1943 and, according to Dent, sometimes claimed to have invented the word gremlins to describe, “meddlesome imps imagined as cause of technical and other problems for aeroplanes.”

“The entry for gremlin has received careful attention from OED’s researchers, editors and etymologists,” wrote Dent. “Our newly revised entry traces the origins of this mysterious word back to 1929 and its use as RAF slang.”

The 1929 version of the word meant, “a lowly or despised person; a menial, a dogsbody, a wretch.” However, a 1938 meaning of the word references gremlins to sprites or imps, which was used by Second World War pilots. According to the Roald Dahl website, the writer enlisted in the Royal Air Force in September 1939, which could have been where he’d heard the word.

The dictionary update also added the word Dahlesque, which is defined as “resembling or characteristic of the works of Roald Dahl.” The word, however, was never used by Dahl himself, but used by others to describe Dahl’s type of writing and use of words. According to Dent’s blog post, the first mention of the word was found in a 1983 quotation on a collection of short stories that was praised for its “Dahlesque delight in the bizarre.”

The update also revised the history of the word splendiferous to include Dahl’s mention in Danny, the Champion of the World as the word changed from resplendent, meaning bright or attractive, to magnificent, meaning impressive in any instance. Frightsome and scrumdiddlyumptious are also revised to include Dahl’s 1982 mentions in The BFG, neither the first mention of the word but important references that developed the meaning.

Dahl was born in Llandaff, Wales on Sept. 13, 1916 and died on Nov. 23, 1990. He began writing books in the 1940s, including James and the Giant Peach and Charlie and the Chocolate Factory among others.

The Oxford Roald Dahl Dictionary includes 393 words that Dahl invented for his books and even a few that never made it, like flubboxed, strodelling and ghost gloamer.