Smile
A smile is an expression of the face that usually expresses sympathy. But this slight rise in the commissures of the lips upwards remains a mystery on many points. Present both in mockery and in consolation, its psychological basis is complex, elusive, mysterious. The smile is at the interface of emotions, experience, personality on the one hand and expression from nervous and muscular processes on the other. The word smile appeared in the Middle Ages, derived from the Latin verb sub-ridere which means taking a laughing or ironic expression, intended to deceive, but the meaning is closer to the Latin word risus which belongs to the vocabulary of laughter. Smile is an expression of the face that is formed by the tension of muscles, especially at the two corners of the mouth, but also around the eyes. It usually expresses pleasure or amusement, but also irony, and thus plays an important social role.