“The word for loving-kindness in Sanskrit is maitri, or metta in Pali, which is related to the word for “friend.” A prosaic translation of this word is simply “friendliness.” In English, friendliness describes a mode of behavior – a friendly way of behaving. That’s certainly a component of the meaning intended here, but loving-kindness is essentially a quality of the mind, although of course it expresses itself in behavior. The essential nature of loving-kindness is a yearning that the person on whom you are focusing your mind be well and happy.”
– Dr. B Alan Wallace, The Four Immeasurables (emphasis added).