This is the 338th most frequent Hungarian word.
reggel
Morning.
'Reggel' here specifies the time of day, indicating part of the morning period.
Reggel korán keltem fel.
I woke up early in the morning.
'Reggel' in this context refers to a specific morning in the past, integral to the setting of the events described.
Egy szép reggel sétáltam a parkban.
One beautiful morning I was walking in the park.
Here, 'reggel' is used as a noun to represent the morning time in general, often associated with the beginning of daily routines.