These are terms that Jung created to describe the opposite-gender self that lives within each of us.
The anima is the feminine component dwelling inside a male's unconscious mind. The animus is the masculine component dwelling inside a female's unconscious mind.
In dreams, this opposite-gender self can be a helper or an antagonist. These dream figures can appear as translations of persons we meet with whom we have a tremendous sense of romantic love or platonic camaraderie. One of Jung's interpreters held that the anima/animus character was only understandable to those who have known true love.
However, our opposite-gender selves may reveal to us negativity in ourselves or negativity we perceive in dealings with the opposite sex. It is important to note that sometimes, when you dream about a person of the opposite sex, they may be representing your own inner self. Carefully consider all persons of the opposite sex in your dreams as a possible appearance of your own anima / animus.
What do these strangers teach you about how you view the opposite sex-do you fear, lust for, or despise these strangers for any apparent reason?