phototherapy

noun

"phototherapy" is a 12-letter English headword indexed on PlainSpell.

The verdict

“phototherapy” is uncommon English (outside the top frequency list), classed as a noun. The kind of spelling people second-guess.

Unranked
below top-frequency English
12
letters

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - The use of light to treat disorders of the skin, and certain mood disorders.

Corpus desk

Index EN-phototherapy · phototherapy · English

phototherapy · unranked · 0 variants · 0 confusables

  • FREQ-UNRANKED Unranked
  • LEN-MEGA 12 letters
  • VOW-5 5 vowels
  • CONFUS-0 No pairs
  • VAR-0 0 variants
  • BOOK-THIN "P" thin
  • PHOTO-UNK Peer pending

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.

Key facts for phototherapy
PropertyValue
Headwordphototherapy
LanguageEnglish
Part of speechNoun
Letters12
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “phototherapy” in English

phototherapyranks outside the top 100,000 English headwords, in the long tail of specialist, archaic, or seldom-used vocabulary, exactly the territory where a reader stops mid-sentence to double-check spelling.

Beyond rank #100,000. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

phototherapy is uncommon English outside the top frequency list, classed as anoun. Rarity is why readers land here mid-draft. Gloss: "The use of light to treat disorders of the skin, and certain mood disorders.".

No generated misspelling entries exist for phototherapy in our index, since its letter pattern doesn't lend itself to common typo substitutions. Our confusable-pair dataset has no match for it, since its spelling is unusual enough that it doesn't cluster with a lookalike.

Etymologically, the entry records: From photo- + therapy. The correct English form is phototherapy, spelled P-H-O-T-O-T-H-E-R-A-P-Y.

Definition

  1. 1
    The use of light to treat disorders of the skin, and certain mood disorders.

Etymology

From photo- + therapy.

Synonyms

light therapy

This word in other languages

Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA). See the methodology for how each field is sourced and updated.

Frequently Asked Questions

How do you spell "phototherapy"?
"phototherapy" is spelled P-H-O-T-O-T-H-E-R-A-P-Y.
What does "phototherapy" mean?
As a noun, "phototherapy" means: The use of light to treat disorders of the skin, and certain mood disorders.
What is the origin of the word "phototherapy"?
From photo- + therapy. See the full etymology section above for more details.
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.

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

Source: FrequencyWords open word-frequency list