a sacral vertebra

左右一対: symmetrical pair, left and right pair

対語: a compound formed with characters of opposite meanings; an antonym

追跡: chase, pursuit; tracking, following / 追惜: a grudge held against someone even after they have died

追跡: to chase, to pursue; to track, to follow / 追惜: to hold a grudge against someone even after they have died

to displease someone (due to one's speech or conduct), to be frowned upon

buying on credit; credit purchase

to buy on credit; to buy on account

stock up

stocking up