A polite morning greeting meaning 'good morning'. In some workplaces it's used at other times as a general greeting.
今朝は元気に『おはようございます』と言って出社した。
This morning I said 'good morning' energetically when I went to work.
学校に着くと、先生に『おはようございます』と挨拶した。
When I arrived at school, I greeted the teacher with 'good morning.'
工場では昼でも『おはようございます』を交わすことがある。
In some factories people exchange 'good morning' even at noon.