Grasmere
geographical name
Gras·mere ˈgras-ˌmir 
lake 1 mile (1.6 kilometers) long in the Lake District of Cumbria, northwestern England
- on duty
- on earth
- on easy street
- on edge
- on end
- on equal terms
- on even keel
- on every hand
- on everybody's lips
- on everyone's lips
- on everyone's/everybody's lips
- on exhibit
- on exhibition
- on faith
- on false pretenses
- on file
- on film
- on fire
- on firm footing
- on firm ground
- on firm ground/footing
- on first acquaintance
- on first-name terms
- on fleek
- on foot