1. Not able to be counted (e.g. because too many to count) 
2. (grammar) of a word that does not have a plural form

Encyclopedia: Uncountable

• overzealous
• Ovibos
• Ovibos moschatus
• Ovid
• oviduct
• Oviedo
• oviform
• Ovimbundu
• ovine
• oviparity
• oviparous
• oviposit
• oviposition
• ovipositor
• oviraptorid
• Ovis
• Ovis ammon
• Ovis aries
• Ovis canadensis
• Ovis montana dalli
• Ovis musimon
• Ovis poli
• Ovis vignei
• ovisac
• Ovocon