Defined in the Merriam-Webster dictionary as "a place of ideal perfection especially in laws, government, and social conditions."
It further tells the origin:
There’s quite literally no place like utopia. In 1516, English humanist Sir Thomas More published a book titled Utopia, which compared social and economic conditions in Europe with those of an ideal society on an imaginary island located off the coast of the Americas. More wanted to imply that the perfect conditions on his fictional island could never really exist, so he called it “Utopia,” a name he created by combining the Greek words ou (“not, no”) and topos (“place”). The earliest generic use of utopia was for an imaginary and indefinitely remote place. The current use of utopia, referring to an ideal place or society, was inspired by More’s description of Utopia’s perfection.
It's the ideal, perfect world—but a world that does not exist.
It doesn't do to dream of a perfect world. It can never happen. There are too many factors in play, too many desires in the world, for all to live in perfect harmony. To not seek more than they're due.
It doesn't do to be blind to inequalities and injustice. To reality.
But cynicism also won't do. Love and kindness and happiness are all around us, as much as greed and hate. Forgiveness, as much as resentment. Hope, as much as resignation.
To accept reality for what it is, but to still try to make a difference. To leave a positive impact in the lives of others. It may never be a perfect world, but it can always be better.