fess vs FOSS, What's the Difference?

Which to use

“fess” is a verb and “FOSS” is a noun - they look or sound alike but fill different roles in a sentence.

#43,640
“fess” frequency rank: #33,655
“FOSS” frequency rank: 77295
confusion score

Side-by-Side Comparison

Feature	fess	FOSS
Definition	To confess; to admit.	Initialism of Free and Open Source Software.

Where the spellings diverge

Shared letters are muted; the letters that actually set fess and FOSS apart are highlighted. They share 3 letters in sequence, which is exactly why the eye skips the difference.

4 ch

fess

4 ch

FOSS

Spelling & Dictionary Insight

These two trip readers on the page rather than in the ear: fess is /fɛs/ while FOSS is /fɒs/. Spoken aloud the problem disappears. In writing it persists, because they differ by a single letter - e in “fess” becomes o in “FOSS”, and the parts of speech differ too (verb vs noun), which is usually the fastest check. Our composite confusion score for this pair is 77295, derived from the frequency rank of both members and their visual similarity.

fess is recorded at frequency rank #43,640, classified as averb, pronounced /fɛs/. FOSS is at rank #33,655, tagged as anoun, pronounced /fɒs/.

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 77295, this pair ranks #27,685 of 530,003 scored English confusable pairs - among the most confusable pairs.

Orthographic DNA of fess vs FOSS

Shared letters: fs. Private to "fess": e. Private to "FOSS": o.

"fess" · 4 letters · shape CVCC · "FOSS" · 4 letters · shape CVCC

Known mistypes of this pair

fess ← efss · ffess · fses
FOSS ← ffoss · fos · fsos · ofss

Frequency comparison

fess#43,640

FOSS#33,655

Source: FrequencyWords open word-frequency list

Frequently Asked Questions

Can "fess" and "FOSS" be used interchangeably?

No - they are not even the same part of speech. "fess" is a verb and "FOSS" a noun, so a sentence built for one is usually ungrammatical with the other.

Which is more common, "fess" or "FOSS"?

"FOSS" is the more common of the two: it sits at frequency rank #33,655 in our English list, against #43,640 for "fess". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

Remembering fess vs FOSS

The fastest way to pick the right one every time.

Check the role first: if you need a verb, it's “fess”; for a noun, it's “FOSS”.
See each word in full, definition, IPA, etymology and its other confusables. Full “fess” entry
Browse more pairs most likely to be confused. Most confusable