A reader asks,
Is it proper to use “thru” as a replacement for “through” in professional writing?
My knee-jerk reaction is, “Good Heavens! Never!”
The spelling “thru” has an entry in the tolerant Merriam-Webster that jumps to through.The OED has no entry for “thru,” although the spelling is listed along with many other historical variations in the through entry.
As a modern alternate spelling of through, “thru” has resisted the efforts of various reform organizations, newspapers, and people in high places to get it accepted by the general reading and writing public.
When the American Philological Association issued a list of words needing reform in 1876, through was on it. Through was on the lists issued by the National Education Association in 1898, and the Simplified Spelling Board in 1906.
Noah Webster, Teddy Roosevelt, and Mark Twain all used their bully pulpits to promote the spelling “thru.” The Chicago Tribune started using “thru” in 1934, but finally gave up in 1975 and went back to through.
That’s not to say that “thru” won’t creep into acceptance in another 50-100 years Certainly texters spell it that way to save time, as many sign painters do to save space. In other contexts, however, for awhile yet, the spelling “thru” screams non-standard.
Why does this particular spelling reform resist acceptance when we’ve happily accepted such changes as theater for theatre, catalog for catalogue, and color for colour?
I think there are two reasons.
One, the word through is introduced to readers at such an early level of literacy that the mind and eye become habituated to it. Because it is among the 200 most commonly used words in English, the beginning reader gets plenty of practice in recognizing it.
Two, “thru” doesn’t look like an English word.
This is one of Romalda Spalding’s rules for “silent final e” in The Writing Road to Reading:
English words don’t end in “u”.
The example she gives is blue. The e is not needed to change the sound of the preceding vowel. Theoretically, we could write “blu,” but the word looks unfinished, like “thru.”
NOTE: Like every rule, Spalding’s has its exceptions. We use several words–most of them borrowed from the French–that end in -u: adieu, bureau, impromptu, etc., but they don’t bother us because they’ve remained sufficiently undigested as to strike us as having a “foreign” spelling. Native English words and fully-digested foreign borrowings look very strange when spelled with a u not followed by e. Consider:
We are strolling down the avenu.
She will argu about everything.
The detective discovered a clu.
I will continu until I’ve finished.
Give the actor his cu.
Give the devil his du.
Bottom line: The spelling “thru” just looks wrong.