費密子一種如電子、質子或中子等自旋為半整數的基本粒子，具有一種使得不可能有多於一個的粒子佔有任何一個特殊的量子力學態的量子力學對稱性
A particle, such as an electron, a proton, or a neutron, having half-integral spin and obeying statistical rules requiring that not more than one in a set of identical particles may occupy a particular quantum state.
非特定的代表某一種類的所有成員或其中一個的；不標誌唯一存在的
Representing one or all of the members of a class; not designating a unique entity.
他克服了一個又一個的困難以後才得脫身。
He managed to cash in only after overcoming one difficulty after another.
