ovsozWhat's the difference?

Quick tell: o is a character, oz is a noun, so they fill different roles in a sentence.

Which to use

“o” is a character and “oz” is a noun - they look or sound alike but fill different roles in a sentence.

#790
“o” frequency rank
#7,037
“oz” frequency rank
7827
confusion score

Side-by-Side Comparison

Feature o oz
Definition The fifteenth letter of the English alphabet, called o and written in the Latin script. Abbreviation of ounce; any of various units of weight and volume.

Where the eye mixes o and oz

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

1 ch
o
2 ch
oz

Spelling & Dictionary Insight

These two trip readers on the page rather than in the ear: o is /ˈəʊ/ while oz is /aʊns/. Spoken aloud the problem disappears. In writing it persists, because they differ by 1 extra letter(s) - “o” sits inside “oz”, and the parts of speech differ too (character vs noun), which is usually the fastest check. Our composite confusion score for this pair is 7827, derived from the frequency rank of both members and their visual similarity.

o is recorded at frequency rank #790, classified as acharacter, pronounced /ˈəʊ/. oz is at rank #7,037, tagged as anoun, pronounced /aʊns/.

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 7827, this pair ranks #505,387 of 530,003 scored English confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of o vs oz

Shared letters: o. Private to "o": -. Private to "oz": z.

"o" · 1 letters · shape V  ·  "oz" · 2 letters · shape VC

Frequently Asked Questions

Can "o" and "oz" be used interchangeably?
No - they are not even the same part of speech. "o" is a character and "oz" a noun, so a sentence built for one is usually ungrammatical with the other.
Which is more common, "o" or "oz"?
"o" is the more common of the two: it sits at frequency rank #790 in our English list, against #7,037 for "oz". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

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

Source: FrequencyWords open word-frequency list