Wiktionary
n. The start of the eighth hour of the day in both the 12-hour and the 24-hour clock; 7:00.
Usage examples of "seven o'clock".
So I had a good rest in the afternoon, and at seven o'clock I presented myself once more at the house in the Avenue du Jura.
You take your cell phone and Louie D's heart to Quaker Bridge Mall and I'll call you at seven o'clock.
It was past seven o'clock, and as dark a night as ever you did see.
On that day, the 25th Fructidor, at seven o'clock in the evening, it was read out by the Public Prosecutor, and listened to by the accused - so the Bulletin tells us - with complete calm and apparent indifference.
The bakery down the street opens at six and I walked there and back, so I guess I saw your friend around seven o'clock.
It was precisely seven o'clock, and if we'd gotten to Stiva's any sooner we would have had to line up outside like fans at a rock concert.