Scrabble is a word game in which two to four players score points by placing tiles, each bearing a single letter, onto a game board divided into a 15×15 grid of squares. The tiles must form words that, in crossword fashion, read left to right in rows or downward in columns and are included in a standard dictionary or lexicon.
American architect Alfred Mosher Butts invented the game in 1938. Scrabble is produced in the United States and Canada by Hasbro, under the brands of both of its subsidiaries, Milton Bradley and Parker Brothers. Mattel owns the rights to manufacture Scrabble outside the U.S. and Canada. The game is sold in 121 countries and is available in more than 30 languages; approximately 150 million sets have been sold worldwide, and roughly one-third of American and half of British homes have a Scrabble set. There are approximately 4,000 Scrabble clubs around the world.
The game is played by two to four players on a square game board imprinted with a 15×15 grid of cells (individually known as "squares"), each of which accommodates a single letter tile. In official club and tournament games, play is between two players or, occasionally, between two teams, each of which collaborates on a single rack.
The board is marked with "premium" squares, which multiply the number of points awarded: eight dark red "triple-word" squares, 17 pale red "double-word" squares, of which one, the center square (H8), is marked with a star or other symbol, 12 dark blue "triple-letter" squares, and 24 pale blue "double-letter" squares. In 2008, Hasbro changed the colors of the premium squares to orange for TW, red for DW, blue for DL, and green for TL, but the original premium square color scheme is still preferred for Scrabble boards used in tournaments.
In an English-language set, the game contains 100 tiles, 98 of which are marked with a letter and a point value ranging from 1 to 10. The number of points for each lettered tile is based on the letter's frequency in standard English.