Regular repeating actions such as sound waves, light waves, or radio waves have a certain frequency, or number of waves per second.

有规律的重复活动如声波、光波、无线电波都有一个特定的频率，或者说是每秒的波动次数。

《柯林斯英汉双解大词典》

The second problem is that Venus exhibits a halo of light when it is seen just outside the Sun's disc.

第二个问题是，当金星在太阳圆盘外被观测到时，它会呈现出光晕。

youdao

The second student said his eyes were full of light green.

第二个学生说他的眼睛充满了浅绿色。

youdao

They had a slightly larger yard than most of their crammed-in neighbors, so they had closed it off with sheets of rusty corrugated metal, and there, at four long wooden tables beneath a string of light bulbs which dangled from a second-story clostra-block window, they served up to thirty customers per night, if the turnover was fast.

NEWYORKER: Ghosts

But after Broad had sent down a wide and two legitimate deliveries - the second of which trapped Denesh Ramdin lbw - the batsmen were offered the light, and Dyson beckoned his batsmen into the pavilion.

BBC: England win after farcical finish

Wait a second, I see a flashing light -- I see one, and it looks like -- yep, yep, the light is Santa.

WHITEHOUSE: The White House