A boon is a helpful benefit or blessing that makes life easier or better. When a new bike path is built in your neighborhood, it's a boon for everyone who wants to cycle safely to school. When a library opens near your house, that's a boon for students who love to read.

The word often appears in the phrase “a boon to” something or someone. Indoor plumbing was a tremendous boon to public health. The invention of the printing press was a boon to education, making books affordable for ordinary people. Even small things can be boons: a sudden rainstorm might be a boon to your garden during a dry summer.

Today, we use it for anything genuinely helpful that arrives when needed. Your excellent memory might be a boon when studying for tests. A friend's sense of humor could be a boon to the whole class on a difficult day.

The opposite feeling comes through in the phrase “bane and boon,” where bane means something harmful or destructive. Technology might be both: a boon for staying connected but a bane when it distracts you from homework.