1. For an indefinite number of successive days
   - day after day

Encyclopedia: Day in day out

• penicillinase-resistant antibiotic
• Penicillium
• penile
• penile implant
• peninsula
• peninsular
• penis
• penis envy
• penitence
• penitent
• penitential
• penitentially
• penitentiary
• penitently
• penknife
• penlight
• penman
• penmanship
• Penn
• penn'orth
• penna
• pennant
• pennate
• Pennatula
• Pennatulidae