TCAS
/ˈtiːˌkæs/
"tcas" is a 4-letter English headword indexed on PlainSpell.
The verdict
“TCAS” is uncommon English (frequency #76,385 among 27,828 “T” headwords), classed as a noun. The kind of spelling people second-guess.
- #76,385
- frequency rank, English
- 27,828
- “T” headwords
According to Wiktionary data (CC BY-SA, analyzed May 6, 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.
| Property | Value |
|---|---|
| Headword | TCAS |
| Language | English |
| Part of speech | Noun |
| IPA | /ˈtiːˌkæs/ |
| Letters | 4 |
| Frequency rank | #76,385 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Where “TCAS” sits in English frequency
Rare enough to double-check
TCAS is uncommon English at frequency #76,385 among 27,828 “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
- 1Initialism 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
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Using “TCAS”
The practical upshot for anyone who landed here from a spell-check.
- The one correct English spelling is T-C-A-S - every other letter order is a misspelling in standard orthography.
- Say it as /ˈtiːˌkæs/ (IPA); tap the speaker on the pronunciation badge to hear it where audio exists.
- Browse more English words and confusable pairs in the same reference. English words
Other uncommon English words near this rank
Data Source
Wiktionary (via kaikki.org), licensed under CC BY-SA & GFDL. Word ordering uses an open word-frequency list; misspelling variants are generated by edit-distance from the correct headword.