foramen magnum

My class is having trouble figuring out how to spell foramen magnum. Some of my students are opting for phonetic spellings, others are just blindly jamming vowels into consonants and praying for success.

frame of magnum, foreman mangus, formen maugnus, form mags, that hole in the head where the spine goes, ‘the large hole in the skull’, a slot for the spine bone

IDK, dude. I’ve simultaneously delighted and horrified by this turn of events.