Provide up to 15 letters available to you. Use up to 2 wildcards (?). Eg. "abcde??"
Filter results by words that start with, or end in a specific set of characters. Eg. "hel" = > (hello, hell)
Filter results for words with a given substring. Eg. "ell" => (hello, stella)
Filter results for words with characters at a specific position. Eg. "j__l_" => (jelly)
Words With Friends® (WWF) includes the most up to date words playable in the game, including words from the social dictionary.
Scrabble® US consists of all words in the official OCTWL dictionary.
Scrabble® UK is based on SOWPODS, played in most of the rest of english speaking countries.
Filter results by word length if you know which length you are looking for.
Scramble games are typically those that take letters, scramble them up and then ask you to make some sort of word out of them. They typically require you to reorganize those letters to also answer a riddle or question. This is great in a number of ways because it challenges you to find a valid answer to the question, and also to recognize the correct word or words that the jumble spells out.
This offers you a good way to strengthen your word game play. Scrabble® and Words with Friends® enthusiasts are well advised to do a bit of jumble solving each day, or at least consider them as a sort of gaming tool.