MARK

1. In telegraphy , one of the two significant conditions of encoding. ( 188 ) Note 1: The complementary significant condition is called a "space." Note 2: In modern digital communications , the two corresponding significant conditions of encoding are called "1" and "0." Synonyms marking pulse , marking signal . 2. A symbol or symbols that indicate the beginning or the end of a field , of a word , or of a data item in a file , record , or block .