Friendship and love both involve an emotional bond, but there are differences in the ways in which they are felt and expressed. True love is composed of three characteristics, according to the book, "The Triangle of Love," by psychologist Robert Sternberg. Love is made up of intimacy, passion and commitment. Friendship doesn't include the last two traits.

Intimacy and Love

The one trait that Sternberg believes characterizes both friendships and love is intimacy. Friends often share secrets, tell each other their problems and form warm bonds in the same way that people in love do. However, it is clear that physical intimacy is different in the two types of relationship. While some friends may hug or kiss each other on the cheek, any other physical form of affection is usually reserved for people who are in love.

The Passion Factor

Passion is an intense feeling of wanting to be deeply involved with another person, often physically. People who are simply friends do not tend to be as passionate about that relationship as they are about someone they are romantically involved with. If you don't have a strong desire to be a fundamental part of another person's world, then you are probably just friends. Passion is an ingredient in whirlwind romances and teenage crushes, but infatuation doesn't constitute true love.

An Essential Ingrediant

Although you can love someone without commitment, for love to be complete, the desire to share a future with someone is important. While friends can come and go and are likely to go off and explore their own interests, love more often involves committing yourself to one person and seeing the relationship through. For some people, expressing commitment means getting married at some point, while others are content to remain unmarried but spend their lives together.

When Feelings Develop

It can be difficult to see where friendship ends and love begins, as people like similar qualities in friendships and committed relationships. Those under the age of 17 experience lower levels of intimacy, commitment and passion in relationships than 18-to-29-year-olds, according to the study, "Perceptions of Love Across the Lifespan; Differences in Passion, Intimacy and Commitment," published in the International Journal of Behavioral Development. So if you are not sure that you have experienced true love, enjoy your friendships and give it time.