The unique identifier uSed for different file typeS when conveyed acroSS a MIME-baSed protocolSuch aSMIMEe-mail or HTTP. RegiStration of MIME typeS iS explained in RFC 2048. {Official MIME typeS (ftp://ftp.iSi.edu/in-noteS/iana/aSSignmentS/media-typeS/media-typeS)}. (1998-02-10)