1. The effect which arises when two or more events or items act upon each other and therefore produce a new effect: Dr. Small told Jenifer to be mindful of the interaction between the two medications she was to take.
2. The spoken communication or discourse between people: At the dinner party, Mrs. Black was pleased with the interaction among the guests.

The charged particle interactions of charged particles associated with the Coulomb forces which they exert on one another.

It includes the forces between two charged particles; such as, between electrons and protons, that according to Coulomb's law is proportional to the product of the charges and inversely proportional to the square of the distance between them and which is either repulsive or attractive, to each other depending on the relationship of the charges.

The principle that one stimulus can influence another one: There are sensory interactions that exist with our bodily functions, such as smell plus texture plus taste equals flavor.

When people hold their noses and close their eyes, and have others feed them various foods, their sensory interactions can cause a slice of apple to be indistinguishable from a chunk of raw potato, a piece of steak may taste like cardboard, and without their odors, a cup of cold coffee can be hard to distinguish from a glass of red wine.

Sensory interaction also influences how well people hear, such as those with hearing losses watching a video with captioning have no trouble hearing the words they are seeing, but when the captioning is turned off, they suddenly realize that they need it.