secvssinWhich spelling fits?

Quick tell: sec is a adjective, sin is a preposition, so they fill different roles in a sentence.

Which to use

“sec” is an adjective and “sin” is a preposition - they look or sound alike but fill different roles in a sentence.

#17,813
“sec” frequency rank
#41
“sin” frequency rank
17854
confusion score

Side-by-Side Comparison

Feature sec sin
Definition Seco Indica la ausencia, carencia o falta de algo.

Where the eye mixes sec and sin

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

3 ch
sec
3 ch
sin

Why the eye confuses sec with sin

These two trip readers on the page rather than in the ear: sec is [sɛk] while sin is [sĩn]. 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 preposition), which is usually the fastest check. Our composite confusion score for this pair is 17854, derived from the frequency rank of both members and their visual similarity.

sec is recorded at frequency rank #17,813, classified as anadj, pronounced [sɛk]. sin is at rank #41, tagged as aprep, pronounced [sĩn].

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 17854, this pair ranks #270,407 of 323,831 scored Spanish confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of sec vs sin

Shared letters: s. Private to "sec": ce. Private to "sin": in.

"sec" · 3 letters · shape CVC  ·  "sin" · 3 letters · shape CVC

Frequently Asked Questions

Is swapping "sec" for "sin" ever safe?
No - they are not even the same part of speech. "sec" is an adjective and "sin" a preposition, so a sentence built for one is usually ungrammatical with the other.
In ordinary Spanish text, does "sec" or "sin" show up more?
"sin" is the more common of the two: it sits at frequency rank #41 in our Spanish list, against #17,813 for "sec". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

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 "sec" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "sin" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #270,407 of 323,831 scored Spanish confusable pairs in this corpus vintage. Corpus statistics
  • "sec" and "sin" also get mixed up with nearby pairs, the highest-scored neighbour is "sec vs stem". Nearby pair

Confusion rank #270,407 of 323,831 scored Spanish pairs, corpus vintage 2026-09-03, not spelling advice.

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

Source: FrequencyWords open word-frequency list