What do interannual, annual and intrannual and interseasonal, seasonal and intraseasonal mean in the context of Oceanography?

Currently I am studying the period of oceanographic phenomena such as El Niño, and I have seen the next concepts: interannual, annual and intrannual and interseasonal, seasonal and intraseasonal. I can understand some of them, but I would like someone could help me to understand them very well in the context of Oceanography. Maybe if you provide me with some literature about those definitions it would be great? Thanks.