Responses are well-considered reactions.
One of the key messages in the book ”10% Happier is the notion of “responding” versus simply “reacting”. Living without mindfulness is a life of reaction. Living mindfully gives you the ability to go beyond reaction, and instead choose how to respond. Meditation helps you move from reaction to response.
This is also what Steven Covery was talking about when he talked about Be Proactive.
This was also identified as one of the 4 Pillars of Toughness.