ob vs os, What's the Difference?

Which to use

“ob” is a conjunction and “os” is a pronoun - they look or sound alike but fill different roles in a sentence.

#30,601
“ob” frequency rank: #449
“os” frequency rank: 31050
confusion score

Side-by-Side Comparison

Feature	ob	os
Definition	Si.	Caso acusativo y dativo del pronombre personal vosotros, una de las formas de la segunda persona del plural en español.

Where the eye mixes ob and os

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

2 ch

Look-alike desk: ob vs os

These two trip readers on the page rather than in the ear: ob is [ɔp] while os is [os]. Spoken aloud the problem disappears. In writing it persists, because they differ by a single letter - b in “ob” becomes s in “os”, and the parts of speech differ too (conjunction vs pronoun), which is usually the fastest check. Our composite confusion score for this pair is 31050, derived from the frequency rank of both members and their visual similarity.

ob is recorded at frequency rank #30,601, classified as aconj, pronounced [ɔp]. os is at rank #449, tagged as apron, pronounced [os].

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 31050, this pair ranks #209,052 of 323,831 scored Spanish confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of ob vs os

Shared letters: o. Private to "ob": b. Private to "os": s.

"ob" · 2 letters · shape VC · "os" · 2 letters · shape VC

Frequently Asked Questions

Do "ob" and "os" mean the same thing in a sentence?

No - they are not even the same part of speech. "ob" is a conjunction and "os" a pronoun, so a sentence built for one is usually ungrammatical with the other.

In ordinary Spanish text, does "ob" or "os" show up more?

"os" is the more common of the two: it sits at frequency rank #449 in our Spanish list, against #30,601 for "ob". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

After this comparison

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

Full dictionary entry for "ob" with definition, IPA, and generated misspellings. Word entry
Full dictionary entry for "os" - compare definitions side by side with the headword page. Word entry
This pair ranks #209,052 of 323,831 scored Spanish confusable pairs in this corpus vintage. Corpus statistics
"ob" and "os" also get mixed up with nearby pairs, the highest-scored neighbour is "ob vs ome". Nearby pair

Confusion rank #209,052 of 323,831 scored Spanish pairs, corpus vintage 2026-09-03, not spelling advice.