The phrasal verb "brighten on" is relatively rare compared to its more common counterparts like "brighten up." Its usage predominantly leans towards informal contexts, often utilized in casual conversation or creative writing to convey the sudden appreciation or enhancement of something abstract, such as a mood or idea. For instance, one might say, "She brightened on at the thought of the upcoming trip," indicating an improvement in her feelings or attitude. Unlike "brighten up," which generally refers to making a place lighter or more cheerful, "brighten on" frequently highlights personal realizations or increased awareness and is less likely to appear in formal writing or professional discourse.
B1
PreIntermediate
1. To become more cheerful or optimistic, often due to an event or another person's actions.
When Jack heard the good news, his face brightened on immediately.
The room brightened on as soon as she started to play the piano.
2. To gain clarity or increase in brightness, often used figuratively to describe an improved perspective.
Mary's understanding of the problem brightened on as she listened to the explanation.
As the day progressed, their plan brightened on and became more feasible.