dash meaning in Information Science terminology / glossary / dictionary is:
A short length of horizontal rule used for punctuation, to separate text, and for decorative effect. In printing, dashes vary in length from the three-em (longest) to the hyphen (shortest). In typing, a dash is made by striking the hyphen key twice in succession (–). In descriptive cataloging, the dash is preceded and followed by a space, but when it is used in subject headings to indicate subdivision, no spaces are included (example: Libraries–Aims and objectives).