operational amplifier - What does the "phase margin" parameter of an opamp imply?

I was reading datasheet of MCP6072. I saw a parameter namely "phase margin" (table 1-2, page 4). As far as I know, "phase margin" is a control engineering term, and implies the phase difference between input and output when the gain is unity. I don't understand the meaning of this term in opamp terminology. The typical phase margin of this opamp is given to be 57^o. That what does it mean?