Robert and I were in a nightclub last night till halfpast one.
Times, Sunday Times (2016)
It was about halfpast three.
Times, Sunday Times (2015)
He used to go at halfpast five in the morning.
Lost Voices of the Edwardians: 19011910 in the words of the Men & Women Who WereThere (2006)
Definition of 'past'
past
(pɑːst, pæst)Explore 'past' in the dictionary
preposition
You use past when you are stating a time which is thirty minutes or less after a particular hour. For example, if it is twenty past six, it is twenty minutes after six o'clock.
Past is also an adverb.
Definition of 'half'
half
(hɑːf, US hæf) (hɑːvz, US hævz)Explore 'half' in the dictionary
phrase
You use half past to refer to a time that is thirty minutes after a particular hour.