Vocabulary Lessons
Structured lessons from beginner to SAT/GRE prep. Interactive flashcards with definitions, pronunciation, and example sentences.
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Structured lessons from beginner to SAT/GRE prep. Interactive flashcards with definitions, pronunciation, and example sentences.
Browse LessonsComprehensive English as a Second Language materials organized by CEFR levels (A1-C2). Grammar, pronunciation, reading, and writing practice.
Explore ESLPlayable HTML5 crossword puzzles organized by difficulty and topic. Challenge yourself with vocabulary-building puzzles.
Play CrosswordsCreate custom crosswords, build vocabulary lists, generate quizzes, and download printable worksheets for your classroom.
Access ToolsThe occurrence and development of events by chance in a happy or beneficial way; the faculty of making fortunate discoveries by accident.
"The discovery of penicillin was a perfect example of serendipity — Alexander Fleming found it when he noticed mold killing bacteria in a petri dish he had accidentally left uncovered."
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Build a strong foundation with the most common English vocabulary. Perfect for beginners and ESL learners.
Master high-frequency SAT words with interactive quiz-style cards. Test your knowledge with immediate feedback.
Professional vocabulary for meetings, presentations, emails, and negotiations. Essential for career advancement.