It's A Sword. Said The Hogfather. They're

Knowing That You Are Going To Die Is, I Suspect, The Beginning Of Wisdom.

The Merest Accident Of Microgeography Had Meant That The First Man To Hear The Voice Of Om, And Who Gave Om His View Of Humans, Was A Shepherd And Not A Goatherd. They Have Quite Different Ways Of Looking At The World, And The Whole Of History Might Have Been Different. For Sheep Are Stupid, And Have To Be Driven. But Goats Are Intelligent, And Need To Be Led.

Esk Felt That Bravery Was Called For, But On A Night Like This Bravery Lasted Only As Long As A Candle Stayed Alight.

What Can The Harvest Hope For, If Not For The Care Of The Reaper Man?

So, Mistletoe, In Fact, Symbolizes Mistletoe.