I’ve been operating with my own vague and personal conceptions of these terms. To me, transnationalism always felt more like “border crossing” while transatlanticism felt more like “ocean crossing” (for no well-developed reason). They each had a different spatial feel for me, so while transnational felt like crossing neighboring borders linearly, transatlantic felt like things and people were crossing large distances through unoccupied “space” (water). If I try to articulate what difference that makes (or why it should make a difference), I find myself blank, but those are just the “sensations” I have had without trying to dig deep and figure out the meanings before. So while transnational and transatlantic to me signify a kind of spatial context and movement, globalization signifies to me a kind of transformation, a “becoming.” Globalization for me has meant creating a network so that communication, movement, transaction, and more can happen across the world–and the resulting state of being connected. Cosmopolitanism in contrast, for me, has meant a philosophy of valuing things, people(s), and cultures as they are and working to promote positive development. So in my conception, transnationalism and transatlanticism contribute to globalization by promoting networks across the world, but cosmopolitanism would only come if the philosophy of the structures and the people involved is one of mutual respect. I’d love to hear how other people conceptualize these ideas!