MTU vs Packet size

I am new in networking stuff and been learning most of it at the job. Recently I came across an issue where an MTU is set to 1500 bytes while the packet size is around 7000 bytes, and when the ping test is performed, 0 packets are received.
I did some research on my mine but have a few queries: does MTU set the upper limit for how big the packet size should be? So setting MTU to 1500 would mean packet size of <=1500 would work and anything more than that may result in packet loss. Is this correct reasoning? I am trying to create an image of how MTU and packet size are related