(Standard Definition TV) A set of digital television (DTV) standards with 480 lines of resolution. All SDTV formats are interlaced, and SDTV pictures are not as sharp as progressive scan EDTV or HDTV (Enhanced Definition or High Definition).

SDTV Vs. SD
"SDTV" may refer to the format or to a TV set that supports it; however, "SD" refers only to the format. See DTV for all the SD/ED/HD specifications.

Sometimes, "SDTV" and "SD" are also used to refer to regular NTSC or PAL television because analog TV and SDTV are nearly equivalent in resolution and have the same 4:3 screen aspect ratio (more square). See interlace, HDTV and EDTV.