This is the 2637th most frequent Japanese word.
明るく
Brightly; cheerfully.
Here, '明るく' is used to describe the manner in which the greeting was performed, implying a cheerful or lively tone.
彼は明るく挨拶しました。
He greeted warmly.
In this example, '明るく' refers to increasing the physical brightness of the room.
部屋をもっと明るくしてください。
Please make the room brighter.
Here, '明るく' is used metaphorically to describe a person's emotional state improving to be more joyful or hopeful.