CD–ROM 
/ˌsi:ˌdi:ˈrɑ:m/ noun
plural CD–ROMs /ˌsi:ˌdi:ˈrɑ:m/ noun : a small plastic disk on which large amounts of information (such as books, pictures, or computer programs) are stored in a form that cannot be changed [count] ▪ The dictionary comes with a free CD-ROM. [noncount] ▪ The dictionary is available on CD-ROM. ◊CD-ROM is an abbreviation of “compact disc read-only memory.” — see picture at computer
