What a waste!
If I was you, I'd just study the word 犠牲 and forget about studying the individual kanji.
Sort of reminds you of 喧嘩, doesn't it? Two kanji with the same left- radical that are only used in conjunction with one another.
If it pleases the gods, it is righteous to sacrifice a cow!
a sacrifice - not only religion. You can sacrifice your happiness for someone else. If a bunch of people die in a train wreck, you can use 犠牲。
a victim, a martyr