The phrase "outer rind" refers to the hard and protective layer that covers the outside of something, like the tough skin on a fruit or the thick outer layer of cheese. Full definition
Lemons consist of a yellow outer rind (skin) and this is where most of the lemon's wonderful tangy flavor is located. (joyofbaking.com)
It's sharp, tangy, has a delicious outer rind, while the inside is still super creamy, and it's totally cheesy. (greenevi.com)
For instance, fragments of the carbon - rich Murchison meteorite, which fell onto Australia in 1969, contain extraterrestrial amino acids that stayed cool beneath a red - hot outer rind. (sciencemag.org)