File that may be read-only

• Adobe's sharable file format
• Many a fillable document
• Suffix for many an email attachment
• Printable format
• JPEG alternative, at times
• Email attachment format
• Adobe image file
• Common download
• File type developed by Adobe

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
by 1992, initialism (acronym) for portable document format , a generic term.