AIf the bride sent you a swatch to match then match it; don't worry about the words she used to describe the colour. People have all different sorts of ideas of what "mint" green is. In the end the right colour is what is important, not the right word. :)
AUmmmmmm. Maybe a hint of the americolor teal? Like a drop at a time in a batch of white fondant? That has more of a green but I can't think of anything.
Maybe combining the teal with sky blue?