word mark (computer hardware)

{{For|the branding term|Wordmark}}

{{Distinguish|Byte order mark}}

{{Distinguish|Word separator}}

In computer hardware, a word mark or flag is a bit in each memory location on some early variable word length computers (e.g., IBM 1401, 1410, 1620) used to mark the end of a word.{{cite book |author=IBM |title=IBM 1401 Data Processing System: Reference Manual |date=April 1962 |id=A24-1403-5 |page=20 |url=http://bitsavers.org/pdf/ibm/1401/A24-1403-5_1401_Reference_Apr62.pdf |access-date=2019-09-30 }} Sometimes the actual bit used as a word mark on a given machine is not called word mark, but has a different name (e.g., flag on the IBM 1620, because on this machine it is multipurpose).{{Cite web|url=https://www-03.ibm.com/ibm/history/exhibits/mainframe/mainframe_PP1620.html|archive-url=https://web.archive.org/web/20050114203104/http://www-03.ibm.com/ibm/history/exhibits/mainframe/mainframe_PP1620.html|url-status=dead|archive-date=January 14, 2005|title=IBM Archives: 1620 Data Processing System|date=23 January 2003}}

The term word mark should not be confused with group mark or with record mark, which are distinct characters.