Thru was one of the more successful initiatives of the spelling reform movement. You see it on highway signs and in certain kinds of military paperwork. From 1939 to 1975, copy editors at the Chicago Tribune changed every through in the paper to thru.
The selling points for thru were easy to understand:
- Fewer letters
- Spelled as it sounds
And yet the dictionary spelling continues to be through, with thru listed as an informal variant.
Here is how through came to look the way it does.
In the early days of the English language (around A.D. 700), through was a four-letter word, and it was spelled as it was pronounced — like this:
þurh
The letter þ, looking like a p with a head-feather, is called a thorn. It dropped out of use after the 1400s, but before then it stood for the sound th. In the spelling of þurh, notice that:
- The r and u were in reverse order back then. This kind of switch-around, called metathesis, happened a lot in the history of the English language. Bird, for example, used to be spelled and pronounced brid.
- The final letter h was pronounced with a Germanic hocking sound, similar to the ch in Achtung!
As þurh evolved toward through, quite a few variant spellings accumulated — including thrughe, throughe, throgh, threu, threw, throu, thrwch, throwch, throche, and thro. These reflected pronunciations in different districts and, over time, by different generations. In Shakespeare’s time (circa 1600), there was growing demand for someone to put a stop to all the variant spellings.
Arrival of THE Dictionary

Johnson’s Dictionary of the English Language (1796 edition). Photo: D’Youville College Archives, Buffalo, NY
Spelling lists had begun to appear in the late 1500s. Samuel Johnson completed the first English dictionary in 1755, followed in 1828 by Noah Webster’s An American Dictionary of the English Language. The success and enduring reputation of Webster’s dictionary were such that even today American dictionaries often have his name in the title.
With dictionaries came the concept of THE dictionary — an authority that ends dispute about the correct spelling and definition of any particular word. At some level, we understand there are many dictionaries produced by different publishers, but when we need to look up a word, we think of ourselves as going to THE dictionary — whichever one it may be. (It’s similar to THE hospital, as in: “Thousands of people go to THE hospital every day.”)
Once the concept of THE dictionary takes hold, it becomes difficult to introduce new spellings. The whole idea of THE dictionary is to extinguish variation. Nevertheless, in the late 1800s, when reformers were clamoring for all kinds of change — the vegetarians, the nudists, the advocates of good government — a spelling reform movement arose, and one of their favorite cases to lay before the public was the common sense of changing through to thru.
Theodore Roosevelt expressed interest in spelling reform, but the movement never rallied enough popular support for a makeover of THE dictionary. By the 1920s, the movement was in decline. Today, you can still see a few stalwart protesters at the national spelling bee, waving signs that say “Enuf!”
The lesson of history appears to be that we are willing to put up with quirks and contradictions, and we are willing to let children and foreigners struggle with silent letters and combinations that produce the most unexpected sounds (hey, we had to learn it; why shouldn’t they?) as long as we have THE dictionary to give the final word.
Modern lexicographers insist their job is to reflect rather than prescribe. But we continue to rely on THE dictionary. Nobody wants to go back to a time when through could also be spelled thrwche.