The word love is used to describe many different feelings, but it’s difficult to define. One common definition describes it as an intense desire for someone or something. This can be expressed in a variety of ways, from lust (physical attraction) to affectionate care and devotion. Other people use the word to describe a feeling of euphoria or an all-encompassing emotional attachment.

Generally, psychologists agree that there are some universal aspects to love. It’s why we forgive our partners for their bad habits, invest time and money into a creative project, or feel devastated when our favorite team loses. Love can be the reason we take on dangerous jobs, make sacrifices for family or friends, or choose to live with HIV.

Love can be seen in nature, art, and literature. It can also be found in the actions of people who promote well-being for others on a global scale, like Martin Luther King Jr., Mahatma Gandhi, Maya Angelou, and Oprah Winfrey. In religion, Christian love is described as the “practice of putting the needs of others before yourself,” or “to will the good of another, even his enemy.” Other religious traditions have various ideas on how to love, but all share the same core values: selflessness, respect, and generosity.

While the idea of love as an emotion is a common one, scientists have studied love in a more scientific way. According to Helen Fisher, chief scientist at Match, when we’re in love, our brains respond in certain ways. For example, a study showed that when people are madly in love, the areas of their brain responsible for pleasure and reward become active. Other studies have shown that when we’re in romantic love, the same areas light up as when we’re given cocaine.

In the Bible, the Old Testament defines love as “to show compassion and forgiveness; to rejoice with those who rejoice and mourn with those who mourn.” The New Testament extends this idea to include all believers. Love can be shown through actions, as in “to offer help and support to those in need; to be kind, generous, and patient,” as well as through words, as in “to speak the truth in kindness.”

When it comes to relationships, biblical love involves caring for and respecting the person you’re in a relationship with, even when they’re not treating you very well. It’s also about being willing to work through conflicts, to forgive and forget, and to be a friend to the person you’re in a relationship to.

The Buddhist teachings on love include the two forms of kama: karuna, which is compassionate care for others and a sense of compulsion to help reduce suffering, and prema, which is loving devotion to a higher power. Various Hindu philosophers and writers have distinguished nine forms of bhakti, or devotional love.