1. A hydrogen atom in an acid that forms a positive ion when the acid dissociates
   - acid hydrogen

Type of: hydrogen atom

• off-base
• off-Broadway
• off-center
• off-centered
• off-centre
• off-centred
• off-color
• off-colour
• off-day
• off-guard
• Robert's Rules of Order
• Roberto Francesco Romolo Bellarmine
• Roberts
• Robertson
• Robeson
• Robespierre
• robin
• Robin Goodfellow
• Robin Hood
• robin redbreast
• robin's plantain
• Robinia
• Robinia hispida
• Robinia pseudoacacia
• Robinia viscosa