letteralmente "da portarsi dietro", ovvero di cui fare tesoro, da tenere sempre presenti

A key fact, point, or idea to be remembered, typically one emerging from a discussion or meeting.
‘the main takeaway for me is that we need to continue to communicate all the things we're doing for our customers’

as modifier ‘the takeaway message’
https://en.oxforddictionaries.com/definition/takeaway