Meanings

negative indication

sign flag

coded form

ISI

sign digit

CDMA

(code) error rate

compaction method

coding theory

code

sign character

separator

character-coded-data-element

explicit scope terminator

long-vowel mark

part of a kanji for which the role is primarily to represent the meaning (as opposed to the pronunciation)

signed

diacritical mark

supplementary symbol (number, punctuation, etc.)

reselling train tickets on the black market