the left part is big seal script of character "Book"
because 2000 years ago, people wrote on bamboo or wooden slips, so book was formed by many slips connected by rope, which is the left part. There was no eraser at that time, if people wrote wrong, they used knife to scrape the surface for rewriting. So "a book + a knife" means "delete".
The person who is responsible for writing documents has brushes and a specific small knife for deleting the wrong characters on bamboo slip. They were officer carrying small knife and brush, not a big knife as a soldier. You can see a few among Qin Terracotta Warriors.
The character is formed by two other pictography characters to express a different meaning, which is an ideogram character.
Its small seal script is
very similar to the big seal script.
Its clerical script is
The right part "Knife", which is a short vertical line plus a vertical line with a hook at the bottom, the short vertical line is not touching the hook line, not like knife anymore.
The song typeface of traditional character is
The song typeface of simplified character is
The difference is very small, actually they have the same number of strokes, which means nothing is simplified.
I need to point out that 删 could mean "Erase" too.
Its Pinyin is "Shan1".