subject requiring memorization; rote-learning material
Refers to a subject or piece of work that must be memorized, often used in educational contexts for material learned by heart.
Historical dates are something you have to memorize.
This exam has a lot of rote memorization.
Compound of 暗記 (memorization) + 物 (thing, matter). The exact historical derivation is uncertain, but the word transparently means 'thing to be memorized'.