labvslumWhich spelling fits?

Which to use

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

#3,506
“lab” frequency rank
#47,736
“lum” frequency rank
51242
confusion score

Side-by-Side Comparison

Feature lab lum
Definition A laboratory. A chimney; also, the top part of a chimney.

Where the eye mixes lab and lum

Muted = shared; highlighted = the visual trap. They share 1 letter in sequence.

3 ch
lab
3 ch
lum

Why the eye confuses lab with lum

A purely visual mix-up. lab (/læb/) and lum (/lʌm/) are said differently, so reading them aloud is the quickest way to catch the wrong one. On the page they stay close: they share most of their letters but differ in 2 positions. Our composite confusion score for this pair is 51242, derived from the frequency rank of both members and their visual similarity.

lab is recorded at frequency rank #3,506, classified as anoun, pronounced /læb/. lum is at rank #47,736, tagged as anoun, pronounced /lʌm/.

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 51242, this pair ranks #167,115 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of lab vs lum

Shared letters: l. Private to "lab": ab. Private to "lum": mu.

"lab" · 3 letters · shape CVC  ·  "lum" · 3 letters · shape CVC

Frequently Asked Questions

Do "lab" and "lum" mean the same thing in a sentence?
No. They are said differently (/læb/ versus /lʌm/) and carry different meanings; reading the sentence aloud is usually enough to catch the wrong one.
Which is more common, "lab" or "lum"?
"lab" is the more common of the two: it sits at frequency rank #3,506 in our English list, against #47,736 for "lum". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

After this comparison

Visual near-miss handled. Browse the word pages or a neighbour when the next look-alike shows up.

  • Full dictionary entry for "lab" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "lum" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #167,115 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • "lab" and "lum" also get mixed up with nearby pairs, the highest-scored neighbour is "LSC vs lum". Nearby pair

Confusion rank #167,115 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list