thesesvsthesisWhich spelling fits?

Which to use

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

#22,243
“theses” frequency rank
#6,636
“thesis” frequency rank
28879
confusion score

Side-by-Side Comparison

Feature theses thesis
Definition plural of thesis Senses relating to logic, rhetoric, etc.

Where the eye mixes theses and thesis

Muted = shared; highlighted = the visual trap. They share 5 letters in sequence.

6 ch
theses
6 ch
thesis

Look-alike desk: theses vs thesis

A purely visual mix-up. theses (/ˈθiːsiːz/) and thesis (/ˈθiːsɪs/) are said differently, so reading them aloud is the quickest way to catch the wrong one. On the page they stay close: they differ by a single letter - e in “theses” becomes i in “thesis”. Our composite confusion score for this pair is 28879, derived from the frequency rank of both members and their visual similarity.

theses is recorded at frequency rank #22,243, classified as anoun, pronounced /ˈθiːsiːz/. thesis is at rank #6,636, tagged as anoun, pronounced /ˈθiːsɪs/.

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 28879, this pair ranks #367,561 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of theses vs thesis

Shared letters: ehst. Private to "theses": -. Private to "thesis": i.

"theses" · 6 letters · shape CCVCVC  ·  "thesis" · 6 letters · shape CCVCVC

Known mistypes of this pair

  • theseshteses · tehses · theess · thesess · thesses · thheses · thsees · ttheses
  • thesishtesis · tehsis · theiss · thesiss · thessi · thessis · thhesis · thseis

Frequently Asked Questions

Do "theses" and "thesis" mean the same thing in a sentence?
No. They are said differently (/ˈθiːsiːz/ versus /ˈθiːsɪs/) and carry different meanings; reading the sentence aloud is usually enough to catch the wrong one.
Which is more common, "theses" or "thesis"?
"thesis" is the more common of the two: it sits at frequency rank #6,636 in our English list, against #22,243 for "theses". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

Useful next steps

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

  • Full dictionary entry for "theses" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "thesis" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #367,561 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • "theses" and "thesis" also get mixed up with nearby pairs, the highest-scored neighbour is "tenses vs theses". 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 #367,561 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