Learn in the textbookFile Formats for Still Images and Documents
DefinitionPDF is an electronic document (電子文書) format that bundles text, images and layout so it displays and prints the same as when it was made, whatever the OS or device.
ExplanationAdobe developed it from PostScript, and it is now an ISO international standard. The fonts used can be embedded in the file, so letter shapes and line breaks stay the same even if the recipient does not have those fonts. Because free reader software and web browsers can open it, it is widely used to distribute application forms and handouts.
AnalogyIt is like the final proof you hand to a print shop. Whichever shop prints it, the result looks the same, so you can send it without worrying about the other side's machines.
Memory hookIt stands for Portable Document Format, and Portable captures the idea that it looks the same wherever you carry it.