This may be a post mostly for our non-native English speaking readers. When to use in or on at any given moment is something native speakers give little thought to, simply because they’ve grown up hearing where these words slot in.
But it can be more confusing for those coming to the language later. And it’s hardly surprising, considering how many definitions these tiny but mighty words can carry. In can be an adverb, noun, adjective or preposition, while on can be an adjective, adverb or preposition. As prepositions alone, they each have over a dozen definitions.
Isabel from Natural England wrote in on the subject: ‘In Spanish, both translate as “en” and I am unsure when to use one or the other in many situations. Is it a matter of learning them by heart or are there any useful rules out there?’
The answer to that (perhaps unfortunately) lies somewhere in between. But for the most common areas where these two words share territory, this downloadable PDF will be a handy reference. Print it off, stick it on your wall or monitor, and the rules will soon be lodged in your mind.