What makes for an “easy baby?”

Since becoming a mom a few months ago, I feel like I’ve heard lots of parents refer to “easy babies.”

Since this is my only baby, and I haven’t been around babies much in life, I have very little frame of reference for exactly what this means.

Obviously I can guess to some extent (takes the breast easily, doesn’t cry unless hungry, sleeps through the night early on, etc) but I was curious how everyone else defines an “easy baby?”