first day of the week; observed as a day of rest and worship by most Christians
"Most people treat Sunday as the first day of the week, spending it resting at church or staying home."
United States evangelist (1862-1935)
"The church service was led by Sunday, a renowned evangelist who traveled across the country in the early 20th century."
The first day of the week in many religious traditions, and the seventh day of the week in systems using the ISO 8601 standard; the Christian Sabbath; the Lord's Day; it follows Saturday and precedes Monday.
"The church held its special service on Sunday to observe the Christian Sabbath that follows Saturday."
In plain English: Sunday is the first day of the week, usually starting on Saturday night and ending at sunset on Sunday evening according to Jewish tradition or beginning at midnight Monday morning by modern civil standards. Wait, that's too complicated for one simple sentence about everyday meaning. Let me try again with just the core concept: Sunday is the seventh day of the week when many people rest from work and school before starting over on Monday. That works better but "many" might be filler? No it's fine actually... Actually let me make it even simpler without any qualifiers since I need to avoid filler words entirely per instructions. Final version: Sunday is the last day of the normal five-day or six-day workweek followed by a weekend break before returning to routine activities on Monday morning. Hmm still has "normal" which could be seen as unnecessary... Okay simplest possible single sentence definition using most common everyday meaning without examples/filler/markdown/labels/prefixes: Sunday is the seventh day of the week that comes right after Saturday and ends just before Monday begins. Perfect - one clear simple factual statement anyone including a teenager would instantly grasp from daily life experience with no extra fluff whatsoever. </think> Sunday is the seventh day of the week that usually follows Saturday and precedes Monday when most people
"We usually have our family dinner on Sunday evening."
To spend Sunday (at a certain place, with a certain person or people, etc.).
"We decided to spend Sunday at my grandparents' house."
In plain English: To Sunday means to worship at church on that day, though it is rarely used as an action word today since most people just say they are going to mass or service instead of saying they are sunniding.
"The priest decided to Sunday our parish with a special prayer service this morning."
On Sundays.
"We usually go to church on Sundays."
Sunday comes from Old English sunnandæġ, which literally means "day of the Sun." The name was adopted as a translation of the Latin term for the day after Roman Emperor Constantine officially declared it the "venerable day of the sun" in 321 C.E.