Wanikani's "radical" names often don't map directly to the actual meaning. They are just used for mnemonics. This happens most when the "radical" isn't a common

Wanikani's "radical" names often don't map directly to the actual meaning. They are just used for mnemonics. This happens most when the "radical" isn't a common/official character in Japanese on it's own right, like 尸. I don't entirely agree with that system, so I often look up the individual radical meanings anyway and add a synonym, but that's Wanikani's method.