What exactly are inodes?

I was taking a look at my cPanel a couple days ago and noticed a section that read, "Inodes Used: 28 % (8375 of 30019)‘’. What are they and what do they do? Are they crucial to running my site? If so, when I reach the max inodes, will I have to upgrade my site? And then how many inodes are there in a premium iFastNet plan?
Thanks in advance,
Blogger Joe

hello https://infinityfree.net/support/inode-limit/

See InfinityFree Support!