Cases of word usage

1) (as used, e.g. on application forms) = first name (forename)

2) an earnest request or appeal (especially a written document signed by a large number of people); a formal application made to a court of law (petition)

3) a mark, object, symbol etc used to represent something: 'mathematical sings' such as '+', '-', 'x', '?'; a word or words, design etc on a board or plate to give a warning, or to give direction; to write (one's name) on (a letter, application form etc) (sign)