In a manner that happens later than expected or needed; occurring with considerable delay.
From 'belated' (adjective, meaning late or delayed) plus the adverbial suffix '-ly.' 'Belated' comes from 'belate,' itself from 'be-' plus 'late,' with the '-ed' ending marking the adjective form.
We still use 'belated' all the time in 'belated birthday wishes,' but most speakers have no idea it comes from the verb 'belate'—the word has fossilized in this one common phrase while the verb has vanished.
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