Belated means coming after the proper time. Belated birthday wishes, a belated apology, belatedly agreed.
It is nearly always attached to greetings and apologies, where the lateness is acknowledged in the word itself — a belated apology admits it should have come sooner. Note that the word is be- plus late plus -ed, and that it first meant overtaken by darkness while travelling.
1adjectivebelatedComing after the proper time.
“Sorry I missed your birthday; here's a belated present.”
belated is a quality of lateness.
From belate + -ed.
Etymology from Wiktionary, CC BY-SA