A well-known person or thing is known about by a lot of people and is therefore famous or familiar. If someone is well-known for a particular activity, a lot of people know about them because of their involvement with that activity.
Hubbard was well known for his work in the field of drug rehabilitation.
哈伯德因在戒毒领域的工作而闻名。
A well-known fact is a fact that is known by people in general.
It is well-known that bamboo shoots are a panda's staple diet.
众所周知,竹笋是熊猫的主要食物。