1. By chance
   - possibly, perhaps, maybe, mayhap [archaic], peradventure [archaic] 
2. [archaic] Through chance, "To sleep, perchance to dream.."
   - by chance [archaic]

Encyclopedia: Perchance

• standing wave
• Standish
• standoff
• standoffish
• standoffishly
• standoffishness
• standpat
• standpipe
• standpoint
• standstill
• standup comedian
• stane
• Stanford
• Stanford University
• Stanford White
• Stanford-Binet test
• stanhope
• stanhopea
• Stanislavsky
• Stanley
• Stanley Baldwin
• Stanley Frank Musial
• Stanley Kubrick
• Stanley Smith Stevens
• Stanley Steamer