a small starlike symbol (*), used in writing and printing as a reference mark or to indicate omission, doubtful matter, etc.
the figure of a star (*) used to mark utterance that would be considered ungrammatical or otherwise unacceptable by native speakers of a language, as in * I enjoy to ski.
the figure of a star (*) used to mark a hypothetical or reconstructed form that is not attested in a text or inscription.