(military) A messenger on a motorcycle. / A postrider or mounted courier (eg the US Pony Express)

The condition of being rideable; the extent to which something is rideable

plural of ridership

(economics) The situation where those who benefit from goods or resources do not pay for them, resulting in a lack of funding and subsequent underprovision.

plural of free rider

plural of rideau

plural of boundary-rider

plural of freedom rider

plural of surf-rider

plural of gang-rider