adverb
separately; individually; apart
Used when actions or states are done or exist independently, not together. Often with verbs like する, 払う, 住む, 考える.
会計は別々に払いましょう。
Let's pay the bill separately.
彼らは別々に住んでいる。
They live apart.
それぞれ means 'each' or 'respectively' and focuses on individual items in a group, while 別々に stresses separation or doing things apart.
Formed by reduplication of 別 (べつ, 'separate') with the adverbial particle に. The iteration mark 々 indicates repetition of the preceding kanji.