rock solid

adj

"rock-solid" is a 9-letter English headword indexed on PlainSpell.

The verdict

“rock solid” is uncommon English (outside the top frequency list), classed as an adjective. The kind of spelling people second-guess.

Unranked
below top-frequency English
10
letters

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - Physically very solid; very difficult to move.

Key facts for rock solid
PropertyValue
Headwordrock solid
LanguageEnglish
Part of speechAdjective
Letters10
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Where “rock solid” sits in English frequency

rock solid falls outside the top-100,000 ranked English words, the long-tail zone of technical, archaic, or low-frequency vocabulary, exactly where readers second-guess spellings most.

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

Rare enough to double-check

rock solid is uncommon English outside the top frequency list, classed as anadjective. Rarity is why readers land here mid-draft. 2 senses are on record.

Zero misspellings are on record for rock solid in our index, since its letter sequence doesn't invite the usual edit-distance slips. No confusable counterpart is on file for this word, a sign it's visually distinctive enough not to be mixed up with another word.

No explicit etymology string is stored for this entry, so its spelling is best explained by sound-to-letter mapping rather than etymology. The correct English form is rock solid, spelled R-O-C-K- -S-O-L-I-D.

Definition

  1. 1
    Physically very solid; very difficult to move.
  2. 2
    Very strong and dependable.

Synonyms

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 "rock solid"?
"rock solid" is spelled R-O-C-K- -S-O-L-I-D.
What does "rock solid" mean?
As an adjective, "rock solid" means: Physically very solid; very difficult to move.
What language does "rock solid" come from?
"rock solid" is a English word. PlainSpell's reference spans five languages -- English, Spanish, Portuguese, French, and German -- with definitions, pronunciations, and spelling data for each.
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.

Using “rock solid”

The practical upshot for anyone who landed here from a spell-check.

  • The one correct English spelling is R-O-C-K- -S-O-L-I-D - every other letter order is a misspelling in standard orthography.
  • Browse more English words and confusable pairs in the same reference. English words
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.

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

Source: FrequencyWords open word-frequency list FrequencyWords open word-frequency list