Please note that this post is subject to change as I learn more about galdr, and the version you read now might not be the version that will be available later. I am posting this quite tentatively because it is undoubtedly unfinished, but all the same, I promised to post new articles on galdr/runic divination semi-regularly, so here we are, and here this is.
So what is galdr?
To put it simply, galdr is the Old Norse word for poems that were possibly, but not for certain, composed in the meter of Galdralag (lit. “meter of magic spells”), and the chanting of these poems was typically accompanied by an action or elaborate ritual meant to bring about a certain effect, like creating a storm, inflicting madness upon a person, causing coins to spontaneously appear in the skinned remains of a dead man’s scrotum (no, that’s not a joke), or making the process of childbirth smoother. Ceremonies involving galdr were performed by vǫlur (singular “vǫlva”).