0-9 | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z
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.