TCAS

/ˈtiːˌkæs/

//ˈtiːˌkæs// noun

"tcas" is a 4-letter English headword indexed on PlainSpell.

The verdict

“TCAS” is uncommon English (frequency #76,385 among 3,151 “T” headwords), classed as a noun. The kind of spelling people second-guess.

#76,385
frequency rank, English
3,151
“T” headwords

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - Initialism of traffic (alert and) collision avoidance system, a system for warning pilots of impending mid-air collisions and telling them what (if any) evasive action to take.

Corpus desk

Index EN-tcas · TCAS · English

TCAS · rank #76,385 · 0 variants · 0 confusables

  • FREQ-RARE #76,385
  • LEN-MID 4 letters
  • VOW-1 1 vowel
  • CONFUS-0 No pairs
  • VAR-0 0 variants
  • BOOK-MID 3,151
  • PHOTO-FINISH tatty

Nearest frequency peer: tatty (-1 rank slots)

Read with this headword: Spelling guide for this pattern

Desk codes from Wiktionary headword shape, FrequencyWords rank tier, confusable-pair count, generated misspelling depth, letter-cohort book size, and photo-finish peer. Not a difficulty grade.

Long-tail ranks near “TCAS”

Sparse band: bars invert rank so rarer forms read shorter

corpus weight

What this shows Long-tail view: where “TCAS” sits against similarly uncommon English ranks.

Source FrequencyWords open word-frequency list As of September 3, 2026
Key facts for TCAS
PropertyValue
HeadwordTCAS
LanguageEnglish
Part of speechNoun
IPA/ˈtiːˌkæs/
Letters4
Frequency rank#76,385
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “TCAS” in English

Word frequency stretches from the small set of words we reach for constantly (left) out to the long tail barely used once in a while (right).TCASfalls in this rarity band:

#1#100#1K#10K#100K
← used constantlyrarely used →

Scale is logarithmic (each tick is 10× rarer). Rare peers in the same band: “tatty” (#76,384), “teamster” (#76,386), “technicals” (#76,387). Among 3,151 “T” headwords, “TCAS” is #76,385. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

TCAS is uncommon English at frequency #76,385 among 3,151 “T” headwords, classed as anoun, transcribed /ˈtiːˌkæs/. Rarity is why readers land here mid-draft. Gloss: "Initialism of traffic (alert and) collision avoidance system, a system for warning pilots of impending mid-air collisions and telling them what (if any) evasive action to take.".

Our edit-distance generator produced no likely misspellings for TCAS, since its letter sequence doesn't invite the usual edit-distance slips. It is not paired with a close-neighbour confusable in our dataset, since its spelling is unusual enough that it doesn't cluster with a lookalike.

Wiktionary doesn't record an etymology for this headword, so its spelling is best explained by sound-to-letter mapping rather than etymology. The correct English form is TCAS, spelled T-C-A-S.

Definition

  1. 1
    Initialism of traffic (alert and) collision avoidance system, a system for warning pilots of impending mid-air collisions and telling them what (if any) evasive action to take.

Synonyms

Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA); frequency ordering uses the FrequencyWords open word-frequency list (2018 English corpus, MIT). See the methodology for how each field is sourced and updated.

Frequently Asked Questions

How do you spell "TCAS"?
"TCAS" is spelled T-C-A-S. The IPA pronunciation is /ˈtiːˌkæs/.
What does "TCAS" mean?
As a noun, "TCAS" means: Initialism of traffic (alert and) collision avoidance system, a system for warning pilots of impending mid-air collisions and telling them what (if any) evasive action to take.
How do you pronounce "TCAS"?
The IPA (International Phonetic Alphabet) transcription for "TCAS" is /ˈtiːˌkæs/. Click the speaker icon on the pronunciation badge above to hear it spoken aloud where audio is available.
What language does "TCAS" come from?
"TCAS" is a English word. You can look up definitions, pronunciations, and spelling data for this and other words across English, Spanish, Portuguese, French, and German on PlainSpell.
Is PlainSpell free to use?
Yes, PlainSpell is a completely free word reference. You can look up definitions, pronunciations, confusable pairs, homophones, and spelling corrections across 5 languages without any sign-up or subscription.

Similar English words by spelling shape

Same letter count and similar misspelling depth for "TCAS", not the corpus desk frequency band.

Same letter count

Frequency-ranked English headwords with 4 letters (nearest by frequency rank).

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

Source: FrequencyWords open word-frequency list