In SFDC world they use the System term 'Camapign' (which really is a Marketing Activity). In Marketo they do the same thing which is called a program.
Each program can connect to SFDC campaign, but they are the same thing.
In SFDC you can create a Parent Campaign which will host your normal campaigns commonlly named 'Child Campaigns'.
Marketo does not have a Parent feature.
You would have many Marketo Programs running for all your Marketing activities that connect to many SFDC Child Campaigns which roll up to a Parent Campaign (Based on a Campaign Theme with many marketing activities).
Hope this helps.