Reading
Shortcuts
Home
All Articles
Read from Another Site
Sources
Wikipedia
Simple Wikipedia
VOA Learning English
Futurity
The Conversation
MIT News
Harvard Gazette
Cambridge News
YDS/YÖKDİL Passages
Topics
Technology
Engineering
Business
Economics
Human
Health
Energy
Biology
Nature
Space
Log in
Sign up
History
Add
on the knocker
• going from door to door canvassing, buying, or selling.
• (of payment) immediately; on demand.
• "he has to pay cash on the knocker"