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to (happen to) see; to notice; to catch sight of
駅で偶然、昔の友人を見掛けて声をかけた。
I happened to see an old friend at the station and called out.
最近彼を見掛けることが多くなってきた。
I've been seeing him more often lately.
珍しい鳥を公園で見掛けて嬉しかった。
I was happy to see a rare bird in the park.