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near; close; beside; vicinity; proximity; besides; while
third person
「側」 has other readings with different meanings.
いつも側にいてくれる。
You're always by my side.
駅の側に新しいカフェができた。
A new café opened near the station.
あなたの側にいられるだけで幸せだと思う。
I think just being by your side makes me happy.