from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A backward virgule ( ).
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The punctuation mark \.
- n. Used erroneously in reference to, or in reading out, the ordinary slash, that is, the punctuation mark /.
- v. To escape (a metacharacter) by prepending a backslash that serves as an escape character, thereby forming an escape sequence.
back + slash, because it is sloped back against the direction of writing, in contrast to the common slash / ("slash, solidus, oblique, forward slash"). (Wiktionary)