You didn't specify a specific type of love Christine, i.e romantic, platonic, or familial. But my one sentence that covers them all is: Love is the unbidden emotion that binds your heart to another, causing you to share their joy and feel their sorrow as if it were your own.
Last time someone asked me and my spontaneous answer was Love is , if the healthy, the desires and the welfare of that person is more important for me than my own ones. so I guess I should repeat it like this. I thouht about love in general, without sexual attraction.
If I had to do it on one word: UN-SELFISH. Otherwise I love the description of love in 1 Corinthians 13. Well used but never old If I speak in the tongues[a] of men and of angels, but have not love, I am only a resounding gong or a clanging cymbal. If I have the gift of prophecy and can fathom all mysteries and all knowledge, and if I have a faith that can move mountains, but have not love, I am nothing. If I give all I possess to the poor and surrender my body to the flames, but have not love, I gain nothing. Love is patient, love is kind. It does not envy, it does not boast, it is not proud. It is not rude, it is not self-seeking, it is not easily angered, it keeps no record of wrongs. Love does not delight in evil but rejoices with the truth. It always protects, always trusts, always hopes, always perseveres. Love never fails. But where there are prophecies, they will cease; where there are tongues, they will be stilled; where there is knowledge, it will pass away. For we know in part and we prophesy in part, but when perfection comes, the imperfect disappears. When I was a child, I talked like a child, I thought like a child, I reasoned like a child. When I became a man, I put childish ways behind me. Now we see but a poor reflection as in a mirror; then we shall see face to face. Now I know in part; then I shall know fully, even as I am fully known. And now these three remain: faith, hope and love. But the greatest of these is love.