The question: what is love?
The answer:

According to dictionary.com:
Love:
[luhv]–noun

1. a profoundly tender, passionate affection for another person.

2. a feeling of warm personal attachment or deep affection, as for a parent, child, or friend.

3. sexual passion or desire.


According to the Bible dictionary:

This word seems to require explanation only in the case of its use by our Lord in his interview with "Simon, the son of Jonas," after his resurrection (John 21:16, 17). When our Lord says, "Lovest thou me?" he uses the Greek word _agapas_; and when Simon answers, he uses the Greek word _philo_, i.e., "I love." This is the usage in the first and second questions put by our Lord; but in the third our Lord uses Simon's word. The distinction between these two Greek words is thus fitly described by Trench:, "_Agapan_ has more of judgment and deliberate choice; _philein_ has more of attachment and peculiar personal affection. Thus the 'Lovest thou' (Gr. agapas) on the lips of the Lord seems to Peter at this moment too cold a word, as though his Lord were keeping him at a distance, or at least not inviting him to draw near, as in the passionate yearning of his heart he desired now to do. Therefore he puts by the word and substitutes his own stronger 'I love' (Gr. philo) in its room. A second time he does the same. And now he has conquered; for when the Lord demands a third time whether he loves him, he does it in the word which alone will satisfy Peter ('Lovest thou,' Gr. phileis), which alone claims from him that personal attachment and affection with which indeed he knows that his heart is full." In 1 Cor. 13 the apostle sets forth the excellency of love, as the word "charity" there is rendered in the Revised Version.

According to poet Carl Sandburg:

Explanations of Love

There is a place where love begins and a place
where love ends.

There is a touch of two hands that foils all dictionaries.

There is a look of eyes fierce as a big Bethlehem open hearth
furnace or a little green-fire acetylene torch.

There are single careless bywords portentous as a
big bend in the Mississippi River.

Hands, eyes, bywords–out of these love makes
battlegrounds and workshops.

There is a pair of shoes love wears and the coming
is a mystery.

There is a warning love sends and the cost of it
is never written till long afterward.

There are explanations of love in all languages
and not one found wiser than this:

There is a place where love begins and a place
where love ends- and love asks nothing.

According to a writer at Time Magazine:

Love's symptoms are familiar enough: a drifting moodiness in thought and behavior, the mad conceit that the entire universe has rolled itself up into the person of the beloved, a conviction that no one on earth has ever felt so torrentially about a fellow creature before. Love is ecstasy and torment, freedom and slavery. Poets and songwriters would be in a fine mess without it. Plus, it makes the world go round. http://www.time.com/time/magazine/article/0,9171,977763,00.html#ixzz1L2ARe4TK

According to www.love.ygoy.com:

• Love is not a necessity, but it is life's greatest gift and luxury. It is to care, to be kind and patient. It is considered as perfect love when a person doesn't expect anything else but love.
• Love is or should be unconditional. And thus is giving and selfless, it is a celebration of what is right and what is true
• Love is undying devotion.
• Love is the desire to be intimate both physically and emotionally.
• Love endures all, hopes all, and bears all. It is believing, sharing and dreaming.
• Love is a feeling of completeness, forgiving, understanding and inspiring.
• Love is the attainment of life's greatest inspiration. It is supporting, but not overbearing.
• Love is a complete expression of oneself or the other. it is being open to each other's expression
• Love can be strong, yet so fragile.
• There are those out there who have not been lucky enough to find it, some never will. In addition, what one would call true love...love in its best, purest, truest sense is even rarer and harder to find.
• The dream of finding and marrying for true love exists and concludes by everything falling into place.

According to me:

I think it is the most powerful thing in the entire universe. I mean people will do absolutely anything for the people that they love. I believe that love can last through anything. That if you really love someone nothing is going to change that. I believe that love never stops. You aren't going to just stop loving someone. If you love someone, at all, you are going to die loving them. You might get hurt by that person and you might wish you hated them, heck you might even really hate them, but at the same time they are always going to be a part of who you are because when you love someone it changes you. They become a part of who you are, and that isn't going to change.

Love is when someone steps into your life and leaves their hand print on your heart.