Element

All atoms that contain the same number of protons.

Musician-satirist Tom Lehrer wrote a song which includes the names of every element known at the time the song was written. Because they are in no particular order, the song is of no particular use to chemistry students, but some of them learn it for fun anyway. It is sung to a tune by Gilbert and Sullivan, replacing Gilbert's lyrics. It opens:

There's antimony, arsenic, aluminum, selenium,

And hydrogen and oxygen and nitrogen and rhenium,

and concludes

These are the only ones of which the news has come to Ha'vard,

And there may be many others, but they haven't been discavard.