Using Lexipedia you can visually map out words and concepts in a clean and friendly interface. No more thumbing through a dictionary, or fumbling through a single-word search; with Lexipedia you can see related words, synonyms, antonyms and fuzzynyms. And best of all, it's absolutely free!
v.
communicate silently and non-verbally by signals or signs; "He signed his disapproval with a dismissive hand gesture"; "The diner signaled the waiters to bring the menu"
v.
send a message or attempt to reach someone by radio, phone, etc.; make a signal to in order to transmit a message; "Hawaii is calling!"; "A transmitter in Samoa was heard calling"
v.
call a meeting; invite or command to meet; "The Wannsee Conference was called to discuss the `Final Solution'"; "The new dean calls meetings every week"