locumvsLouWhat's the difference?

Quick tell: locum is a noun, Lou is a name, so they fill different roles in a sentence.

Which to use

“locum” is a noun and “Lou” is a name - they look or sound alike but fill different roles in a sentence.

#47,732
“locum” frequency rank
#7,811
“Lou” frequency rank
55543
confusion score

Side-by-Side Comparison

Feature locum Lou
Definition Ellipsis of locum tenens. A unisex given name.

Where the eye mixes locum and Lou

Muted = shared; highlighted = the visual trap. They share 3 letters in sequence. locum runs 5 letters (CVCVC) against Lou's 3 (CVV) - the length gap alone is often enough to separate them once you know to check it.

5 ch
locum
3 ch
Lou

Why the eye confuses locum with Lou

These two trip readers on the page rather than in the ear: locum is /ˈləʊkəm/ while Lou is /luː/. Spoken aloud the problem disappears. In writing it persists, because they differ by 2 letter(s) in length, and the parts of speech differ too (noun vs name), which is usually the fastest check. Our composite confusion score for this pair is 55543, derived from the frequency rank of both members and their visual similarity.

locum is recorded at frequency rank #47,732, classified as anoun, pronounced /ˈləʊkəm/. Lou is at rank #7,811, tagged as aname, pronounced /luː/.

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 55543, this pair ranks #132,835 of 530,003 scored English confusable pairs - among the most confusable pairs.

Orthographic DNA of locum vs Lou

Shared letters: lou. Private to "locum": cm. Private to "Lou": -.

"locum" · 5 letters · shape CVCVC  ·  "Lou" · 3 letters · shape CVV

Known mistypes of this pair

  • locum ← lcoum · llocum · loccum · locmu · locumm · loucm · olcum

Frequently Asked Questions

Is swapping "locum" for "Lou" ever safe?
No - they are not even the same part of speech. "locum" is a noun and "Lou" a name, so a sentence built for one is usually ungrammatical with the other.
In ordinary English text, does "locum" or "Lou" show up more?
"Lou" is the more common of the two: it sits at frequency rank #7,811 in our English list, against #47,732 for "locum". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

Useful next steps

Pronunciation already separates them, if the page still looks alike, the dictionary links below settle it.

  • Full dictionary entry for "locum" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "Lou" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #132,835 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • "locum" and "Lou" also get mixed up with nearby pairs, the highest-scored neighbour is "lockup vs locum". Nearby pair
  • Recorded mistypes exist for at least one side of this pair, useful when a spell-checker or OCR lands on the wrong form. See mistypes

Confusion rank #132,835 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