Lt vs lux, What's the Difference?

Which to use

“Lt” and “lux” are a confusable English pair: similar on the page, but distinct in meaning, check the gloss before you choose.

#5,608
“Lt” frequency rank: #18,878
“lux” frequency rank: 24486
confusion score

Side-by-Side Comparison

Feature	Lt	lux
Definition	Abbreviation of lieutenant, particularly as used in a title.	In the International System of Units, the derived unit of illuminance or illumination; one lumen per square metre. Symbol: lx

Letter map: Lt vs lux

Shared letters muted; letters that set Lt and lux apart highlighted. Shared run: 1.

2 ch

3 ch

lux

Corpus notes: Lt and lux

Lt and lux are indexed as a confusable English pair. We have no recorded pronunciation or part of speech for both members, so the spelling overlap is what we can show you: they differ by 1 letter(s) in length. Our composite confusion score for this pair is 24486, derived from the frequency rank of both members and their visual similarity.

Lt is recorded at frequency rank #5,608, classified as anoun. lux is at rank #18,878, tagged as anoun, pronounced /lʌks/.

Glosses for this pair are partially populated in our dataset, but the full side-by-side definitions above should still guide you to the right choice.

With a confusion score of 24486, this pair ranks #401,580 of 530,003 scored English confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of Lt vs lux

Shared letters: l. Private to "Lt": t. Private to "lux": ux.

"Lt" · 2 letters · shape CC · "lux" · 3 letters · shape CVC

Frequently Asked Questions

Can "Lt" and "lux" be used interchangeably?

No. They differ by 1 letter(s) in length, but the dictionary glosses above give them different meanings, so swapping one for the other changes what the sentence says.

Frequency check: "Lt" vs "lux" - which ranks higher?

"Lt" is the more common of the two: it sits at frequency rank #5,608 in our English list, against #18,878 for "lux". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

After this comparison

Pair "Lt" vs "lux" is on the table, pick a follow-up below.

Full dictionary entry for "Lt" with definition, IPA, and generated misspellings. Word entry
Full dictionary entry for "lux" - compare definitions side by side with the headword page. Word entry
This pair ranks #401,580 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
"Lt" and "lux" also get mixed up with nearby pairs, the highest-scored neighbour is "LSC vs lux". Nearby pair

Confusion rank #401,580 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.