Eiwaz is the rune of the Yew tree. It is therefore associated with archery, medicine, and Yggdrasil (the World Tree which, in some translations, is a yew). I therefore associate this card with The Knights of the Minor Arcana generally, and more specifically with The Knight of Wands.
Yggdrasil literally means Odin’s Steed. In any Norse inspired Tarot deck, it is represented by Major Arcana 21, The World. It is the tree which connects the nine worlds of the Norse Mythos: Midgard (Earth); Asgard and Vanaheim (where the gods live); Niflheim, Hel, and Jotunheim (cold places); Muspelheim (a land of fire to the South); and Svartalfheim and Alfheim (fairy realms where the dwarves and elves live, respectively).
Any Christian readers, or people not familiar with Norse cosmology, will look at Hel and say, “Wait, cold?” Yes. Hel was originally a corner of Niflheim, before Odin carved it off for Loki’s monstrous daughter, also named Hel. She now runs Hel as a resting place for those who die peacefully at home. It is a place of feasting and joy, and I hear she maintains a warm fire there to stave off Niflheim’s chill.
I more frequently read Eiwaz in its association with Archery as a Rune to go out into the world in order to protect yourself and those you care about. If gun rights advocates were intellectually honest and not just saying they want to be able to shoot people of color, they would be using this rune as one of their symbols. (They aren’t, they use the Armanen version of Odal, instead.)
When this rune comes up in a reading, I usually interpret it as a rune of protection. Go out and protect those you care about. The most effective way to do this in the modern day is to talk to people, but don’t let them walk all over you. This rune is upright, like the spine of a person who is standing up for what they believe in.
The exception is when I am doing a reading for a fellow witch about their magick. In that case, this is a rune of the journey between the worlds. It is still a rune of going out, but the focus is more on journeying to various realms of faerie. You might need to talk to the gods, or to the elves or the dwarves. You might even need to go kick a giant’s butt. Do what you need to do.
Use in Magick:
When I use this rune in my magick, it is far more often in the sense of the connections between the worlds. When I need to journey to any of the nine realms of Yggdrasil, I will use this rune to guide my way. This is not to be confused with Raidho, which is a rune of the physical journey. Eiwaz is specifically a spiritual journey.