I'm trying to understand the etymology of injunction. To wit, how did
compound to mean
Late Latin iniunctionem (nominative iniunctio) "a command,"
Jungere means to bind things together. With the in- "into, onto" prefix, it means to attach one thing onto something else.
Literally, this is used for physical objects, like vines joining themselves onto a wall. But metaphorically, it can mean to attach new restrictions or punishments onto someone.
Thus, an injunction is when these restrictions and commands are attached to someone.
EDIT: In the comments, Cerberus has pointed out a connection with jugum "yoke", which is another nice analogy for a punishment attached to someone.