What is love?

The term we call love is applied to so many circumstances that it is difficult to describe it in a single context.
There is a love for all humans(because we are the same species), a love for all animals(because they are also living things, like humans)
a love for all Indians, a love for all people speaking our language,
a love for all people in your family(or not! ) and so on...

Then there is a specific love, targeted at a particular entity(living or non-living)
Love for your mom, dad, siblings.
Love for your BF, GF, Husband, Wife, kids, personalities,
Love for your guitar, for your cricket bat, for your 15 year old diary, for your keyboard and mouse(!!).

Then, there is the love for intangibles.
Love for history, love for science, love for mathematics,
love for laughter, love for God, love for love(!)...

The point is, for each kind of love there are limits you are ready to go to(or break!); in physical, mental, emotional, social, financial, spiritual realms.
Love can happen more than once in each of these fields depending on the limits that your mind is ready to go to, or has already gone to, while loving any of them.
After falling in love with one entity(living/non-living, tangible/intangible), if nothing else seems more important than it for the rest of their lives, that is what people term true love.
It's loss might lead some people into deep melancholy, depression, and ...you know the possibilities.
Some others live contentedly with whatever love they have around them.

Some others, go out in the world and experience the love for all the other things present in this world with an open mind, in the hope that there will be something else which will strike a chord with their mind. That is when they find the 'something else' which seems more important than anything else. Introducing, the second true love. :)and so on...
Now there could be more than 1 true loves at the same time too. But, the limits for them should be a non-contradicting/non-competing set.(For eg. entities in different realms, perfectly drawn boundaries etc etc). This is rarely possible.

All hunky-dory? Not quite.
Now, the problem with humans is, they change; physically, mentally, emotionally, and in all other aspects possible.
Hence the feeling of love, as it applies to different entities the person loves, also changes. It increases or decreases, the limits in the mind regarding these things change, and love itself might lose its importance in one's life(suicidal tendencies!! (alias, love of suicide :P)).
So the definition of love is different for each person and for each context, and what love means for you depends on your mental make up and the circumstances and entities you will encounter in your life.