The Difference Between Round and Round

I unlocked more vocabulary on WaniKani today and I came across something fun and odd. Previously I had learned the word 丸い which means round. Today I learned 円い which also means round. 丸い refers to things that are more 3 dimensional like a ball or a cylinder being round. 円い refers to flat things that are round like a drawn circle or a coin. 円 is the character for ￥ or yen. So if you can think of a coin being flat and round, that's what you would use it for.

The kicker is 丸い and 円い are both pronounced まるい! Two different words meaning the same thing but written differently depending on context. Maybe a little confusing, but I think it makes sense to. In English we would need to write that something is flat and round to distinguish it from something that is just round. At least 日本語 has a nifty shortcut.