rider
noun
[ ˈrʌɪdə ]
• a person who is riding or who can ride a horse, bicycle, motorcycle, etc.
• "two riders approached the cottage"
• a condition or proviso added to something already agreed.
• "one rider to the deal—if the hurricane heads north, we run for shelter"
• a small weight positioned on the beam of a balance for fine adjustment.
Origin:
late Old English rīdere ‘mounted warrior, knight’ (see ride, -er1).
