おはようございます (o-ha-yo-u-go-za-i-ma-su)
Definition: Good morning
*used until around 6am, and between friends and family, it is usually shortened to おはよう (o-ha-yo-u)
こんにちは (ko-n-ni-chi-wa)
Definition: Good afternoon
*used from 11am to 6pm, not used between members of the same family
こんばんは (ko-n-ba-n-wa)
Definition: Good evening
*used after 6pm, not used between members of the same family
さようなら (sa-yo-u-na-ra)
Definition: Goodbye
おやすみなさい (o-ya-su-mi-na-sa-i)
Definition: Goodnight