Vocabulary Building

If you read a lot, you grow vocabulary as a side-effect — but deliberate practice (especially for SAT / GRE / language learners) compounds faster. Pair with Spaced Repetition (Anki) and Language / Bilingual Reading. For kids see Children's Reading.

Hosted vocabulary apps

• ★ Vocabulary.com — paid + free; the most-loved SAT-shape vocab trainer; adaptive quizzes; context-rich definitions; large list library.
  • https://www.vocabulary.com
• Magoosh Vocabulary Builder — free; iOS / Android; GRE-shape; 1200 words.
• Membean — paid; school-licensed; deep root-of-the-word focus.
• Quizlet — paid + free; flashcard-style; classroom default. See Spaced Repetition.
• PowerVocab / WordUp — paid + free; mobile.

FOSS / DIY

• ★ Anki + a SAT / GRE deck — free; tens of thousands of community decks. See Spaced Repetition.
• Mnemosyne / Mochi / RemNote — same idea, alternative SRS.
• Migaku / JPDB / Clozemaster — language-immersion-flavoured for non-English vocab.

Browser / dictionary lookup

• ★ Wiktionary + native browser dictionary — free; right-click → Look Up on macOS / iOS is the best dictionary integration on any platform.
• ★ Kindle / Kobo built-in dictionary + Wikipedia — free; the killer e-reader feature.
• Mate Translate — paid Mac; pop-up dictionary + translation.
• Google Dictionary (extension) — free Chrome.
• Click2Dict — free; older.

Word-of-the-day / passive

• Dictionary.com Word of the Day — free.
• Merriam-Webster Word of the Day — free; the audio podcast version is great.
• A.Word.A.Day (wordsmith.org) — free email; running since 1994.
• Oxford English Dictionary Word of the Day — free email.

Test prep (SAT / GRE / TOEFL)

• ★ Vocabulary.com SAT lists — paid; the modern default.
• Magoosh GRE Vocabulary Builder — free.
• Khan Academy SAT prep — free; full SAT including vocab in context.
• Anki + a vetted SAT / GRE deck — free; cheaper and more efficient than commercial apps.

Style / writing-flavoured (vocab as output)

• Wordtune — paid + free; rewriter; gives synonym-aware paraphrases.
• Hemingway Editor — free + paid; plainer-language flagger.
• OneLook Reverse Dictionary — free; "what's the word that means…?".
• Power Thesaurus — free; community-ranked.

Patterns

• ★ Read above your level + look up everything. The Kindle dictionary tap is the most efficient vocabulary-builder ever made.
• Anki the long-tail. SAT vocab decks → review daily for 6 months → done forever.
• Read in two languages. See Language / Bilingual Reading.
• Track unknown words — Kindle's Vocabulary Builder is built in; export to Anki.

Pick this if…

• Default SAT-shape vocab: Vocabulary.com.
• Free GRE prep: Magoosh Vocabulary Builder.
• Schools: Membean.
• DIY / FOSS: Anki + community decks.
• Passive learner: Merriam-Webster Word of the Day.
• Context-rich (read in the wild): Kindle / Kobo dictionary lookup.