My username has a fairly complicated story, but it might be interesting.
kôshin or koushin (depending on how you want to transcribe it) is a japanese compound word, consisting of kô (紅) and shin (心).
紅 (kô or kurenai) means crimson or scarlet and is often used in japanese literature to signify fall. My favorite japanese book is called The Scarlet Gang of Asakusa and that also played a role in me chosing this name.
心 (shin or kokoro) means heart. I used to spray and draw comics a lot when I was younger. Back then I'd sign everything with shin. Because japanese has a lot of homonyms, I'd change the meaning of what shin meant to me, based on my mood. Sometimes it would be 真(shin), which means truth or sincerity and sometimes it would be 新(shin) which means new, like a new beginning or something.
紅心 (kôshin) as such doesn't exist in the japanese language, it's a compound word that I thought of. I think there's a word like that in chinese, but that's not what I mean haha.
The reason that I added both these words together is because there's a word in japanese called sekishin (赤心), which combines the signs for red and heart. The meaning of this word is true heart, or something that comes from the bottom of the heart.
With me replacing the red with scarlet, I try to put an emphasis on the fact, that depression might be felt from deep within the bottom of ones heart, but beneath that, if we go deeper, there's a part that's not affected by the depression. A part that shines through from time to time. Something that gives me hope for improvement.