rid·ing 2 
(rīdĭng)
(rīdĭng)n.
1. An administrative division or electoral division in Canada.
2. Any one of three former administrative divisions of Yorkshire, England.
[Middle English, alteration of trithing, from Old English *thrithing, from Old Norse thridhjungr, third part, from thridhi, third; see trei- in the Appendix of Indo-European roots.]