INODES represent the amount of all the files located on your hosting account. For example, a mail stored in your account will be 1 inode, a mail which contained 2 attachments will be 3 inodes. Any image file, video, HTML file, folder and script file are considered inodes.
What happens if INODE limit is reached?
Once the INODE limit is reached, you will no longer be able to create any more additional files. Your website might also stop working properly. The solution is to remove any unused website files (logs, uploads, images), emails or empty your mailbox spam folder.