It refers to the time of day. 01:30 or 13:30
30 minutes after the hour. "Its half past 1." it's 1:30!
Half past 1:30 is 2 o'clock
'Half past one' is the time. However, to specify whether it is 'am' or 'pm' We would write 1:30 am , which is the 'middle of the night. or 1:30 pm , which just past lunch time in the middle of the day. 'am/pm' is the initials of the Latin phrase 'Ante/Post Meridian' , which means 'before/after noon'. On the '24' hour clock 1:30 am is 0130 hours 1:30 pm is 1330 hours. On the 24 hour clock, the first two numbers range from '0' to '23'. (Hours) The second two numbers range from '0 to 59' ( minutes). NB There is no such time as '0000' nor ' 2400' on the 24 hour clock , as it is exactly midnight, but which/day/date? So it is never used.
'Thirty minutes past the given hour. Or more rarely, 30 minutes to the next given hour. NB 'Quarter past ' means 15 minutes past the given hours. The miniute hand is at '3' on the clock dial 'Quarter to' means 15 minutes to the next given hour. The minute hand is at '9' on the clock dial. ' o'clock ' as in seven o'clock, means 'seven hours of the clock'. The minute hand is at '12' and the hours hand is at '7'.
3:30
4:30
9:30
1:30
4.35
6:30 i suppose
half past 6
3:30