spi vs STS, What's the Difference?

Which to use

“spi” is an adjective and “STS” is a noun - they look or sound alike but fill different roles in a sentence.

#49,369
“spi” frequency rank: #40,514
“STS” frequency rank: 89883
confusion score

Side-by-Side Comparison

Feature	spi	STS
Definition	Spirituel (au sens religieux).	Navette spatiale américaine ayant effectué 135 vols pour l'agence spatiale américaine (NASA) entre le 12 avril 1981 et juillet 2011.

Where the spellings diverge

Shared letters are muted; the letters that actually set spi and STS apart are highlighted. They share 1 letter in sequence, which is exactly why the eye skips the difference.

3 ch

spi

3 ch

STS

Spelling & Dictionary Insight

These two trip readers on the page rather than in the ear: spi is \spi\ while STS is \ɛs te ɛs\. Spoken aloud the problem disappears. In writing it persists, because they share most of their letters but differ in 2 positions, and the parts of speech differ too (adjective vs noun), which is usually the fastest check. Our composite confusion score for this pair is 89883, derived from the frequency rank of both members and their visual similarity.

spi is recorded at frequency rank #49,369, classified as anadj, pronounced \spi\. STS is at rank #40,514, tagged as anoun, pronounced \ɛs te ɛs\.

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 89883, this pair ranks #5,338 of 440,172 scored French confusable pairs - among the most confusable pairs.

Orthographic DNA of spi vs STS

Shared letters: s. Private to "spi": ip. Private to "STS": t.

"spi" · 3 letters · shape CCV · "STS" · 3 letters · shape CCC

Frequency comparison

spi#49,369

STS#40,514

Source: FrequencyWords open word-frequency list

Frequently Asked Questions

Can "spi" and "STS" be used interchangeably?

No - they are not even the same part of speech. "spi" is an adjective and "STS" a noun, so a sentence built for one is usually ungrammatical with the other.

Which is more common, "spi" or "STS"?

"STS" is the more common of the two: it sits at frequency rank #40,514 in our French list, against #49,369 for "spi". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

Remembering spi vs STS

The fastest way to pick the right one every time.

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