21-letter words containing d, i, m, e, n, s
- transactinide element — any element having an atomic number higher than 103, the last of the actinide series. These superheavy, radioactive elements are extremely short-lived, and can only be created in the laboratory.
- universal disk format — (storage, standard) (UDF) A CD-ROM file system standard that is required for DVD ROMs. UDF is the OSTA's replacement for the ISO 9660 file system used on CD-ROMs, but will be mostly used on DVD. DVD multimedia disks use UDF to contain MPEG audio and video streams. To read DVDs you need a DVD drive, the kernel driver for the drive, MPEG video support, and a UDF driver. DVDs containing both UDF filesystems and ISO 9660 filesystems can be read without UDF support. UDF can also be used by CD-R and CD-RW recorders in packet writing mode.
- ventriloquist's dummy — a puppet which is operated by a ventriloquist and made to appear to talk
- vladivostok agreement — a preliminary arms control accord concluded by Soviet leader Leonid Brezhnev and U.S. President Gerald Ford in Vladivostok, U.S.S.R., in December 1974.
- xeroderma pigmentosum — a rare inherited disease characterized by sensitivity to ultraviolet light, exposure resulting in lesions and tumors of the skin and eyes.