filename extension

Noun filename extension has 1 sense

• filename extension(n = noun.communication) extension, file name extension - a string of characters beginning with a period and followed by one or more letters; the optional second part of a PC computer filename; "most applications provide extensions for the files they create"; "most BASIC files use the filename extension .BAS"
is a part of computer file name, computer filename, file name, filename
is a kind of string