There are two words (or rather, two forms of a word) for “both” in Russian language:
оба — for masculine and neutral nouns
обе — for feminine nouns.
Examples:
masc.
оба носка — both socks
оба друга — both friends
neutral
оба ведра — both buckets
оба солнца — both suns
fem.
обе девушки — both girls
обе стороны — both sides
Sentences: