1. Indicates an affirmative response
   - ay, aye, sure, uh-huh, yah [UK], yea, yeah, yep, yes, ya [S.Africa]

Encyclopedia: Yup

• operative field
• operatively
• operator
• operator gene
• opercular
• operculate
• operculated
• operculum
• operetta
• operon
• operose
• operoseness
• Opheodrys
• Opheodrys aestivus
• Opheodrys vernalis
• Ophidia
• ophidian
• Ophidiidae
• ophidism
• Ophiodon
• Ophiodon elongatus
• Ophiodontidae
• Ophioglossaceae
• Ophioglossales
• Ophioglossum