Touching

Touching is having or getting a zero distance; in geometry it refers especially to a tangent line or curve (cf. collision). This term can be used to describe interaction between any physical objects. In medicine, the colloquial term "touch" is usually replaced with somatic senses, to better reflect the variety of mechanisms involved.
One can also be emotionally touched. In this metaphorical sense it refers to some action or object that evokes a sad or joyful emotion. For example, to say "I was touched by your letter" would imply the reader felt joy or sadness when reading it.