ETYM For thriding, Icel. thrithjungr the third part, from thrithi third, akin to Eng. third. Related to Third.
1. Riding a horse as a means of transportation; SYN. horseback riding.
2. Riding a horse as a sport; SYN. horseback riding, equitation.
3. One of the three administrative jurisdictions into which Yorkshire, England, was formerly divided.
4. An administrative jurisdiction or electoral district in a British dominion (as Canada).