dinnertime; suppertime
Refers to the time of the evening meal. Commonly used in everyday conversation.
The phone rang at dinnertime.
The family gathers at suppertime.
夕方 means 'evening' (a broader time period), while 夕食時 is specifically the time when dinner is eaten.
Compound of 夕食 (yūshoku, 'evening meal') and 時 (ji, 'time').