Originally Posted by: Scytmo

I have a Squire Stratocaster and it has two little pillars on the headstock that each bind two strings together (photo below). I've found it impossible to Google what these are for - because I don't know what they're called (you have to know the answer in order to ask the question!)

Their purpose is to put enough downward pressure on the strings after they cross the nut to put tension on the string to make the guitar playable. Some guitars have angled headstocks to achieve the same purpose. Some guitars have staggered tuning posts to make string trees unecessary.

Look here:

https://www.premierguitar.com/articles/24295-guitar-shop-101-happy-little-string-trees

I also briefly mention the string tree in this lesson.

https://www.guitartricks.com/lesson.php?input=15809&s_id=1121

Hope that helps!