sunday

Sun‧day /ˈsʌndi, -deɪ/ BrE AmE noun [uncountable and countable]
[Language: Old English; Origin: sunnandæg]
1. (written abbreviation Sun.) the day between Saturday and Monday
on Sunday
We’re going to a match on Sunday.
What are you doing Sunday? American English
Sunday morning/afternoon etc
Sunday nights are usually pretty quiet.
last Sunday
It was our wedding anniversary last Sunday.
this Sunday
There’s another antiques market this Sunday.
next Sunday (=Sunday of next week)
We’ll announce the winners next Sunday.
a Sunday (=one of the Sundays in the year)
Finding a dentist on a Sunday can be very difficult.
2. your Sunday best your best clothes, worn only for special occasions or for church
3. Sunday driver an insulting expression meaning someone who annoys other people by driving too slowly
⇨ never in a month of Sundays at ↑month(6)

Oxford Advanced Learner's Dictionary

Sunday

Sun·day [Sunday Sundays] [ˈsʌndeɪ] [ˈsʌndeɪ] [ˈsʌndi] [ˈsʌndi] noun (abbr. Sun.)

1. countable, uncountable the day of the week after Saturday and before Monday, thought of as either the first or the last day of the week To see how Sunday is used, look at the examples at Monday.

2. countable, usually plural (BrE, informal) a newspaper published on a Sunday
more at in a month of Sundays at month
Idiom: your Sunday best
Word Origin:

Old English Sunnandæg ‘day of the sun’, translation of Latin dies solis; compare with Dutch zondag and German Sonntag.

Cambridge Advanced Learner's Dictionary

Cambridge Advanced Learner's Dictionary - 4th Edition

Sunday / ˈsʌn.deɪ / noun [ C or U ] ( written abbreviation Sun. )

A1 the day of the week after Saturday and before Monday, when most people in Western countries do not go to work:

We're going to visit my aunt and uncle on Sunday.

They go to church on Sundays.

The choir is giving a concert next Sunday.

I haven't done any exercise since last Sunday.

New Year's Day this year is a Sunday.

Sunday morning/afternoon/evening/night

In Britain the traditional Sunday lunch consists of roast meat.

Collins COBUILD Advanced Learner’s English Dictionary

Sunday

/sʌndeɪ, -di/
(Sundays)

Sunday is the day after Saturday and before Monday.
I thought we might go for a drive on Sunday...
Naomi used to go to church in Granville every Sunday.

Merriam-Webster's Advanced Learner's Dictionary

Merriam-Webster's Advanced Learner's Dictionary:

Sunday

Sun·day /ˈsʌnˌdeɪ/ noun, pl -days : the day of the week between Saturday and Monday

[count]

• She visited me last Sunday.
• What are you doing this/next Sunday? = What are you doing this coming Sunday?
• We go to church on Sundays. [=every Sunday]
• My birthday falls on a Sunday this year.
• (Brit) Next week I'll arrive on the Monday and leave on the Sunday.

[noncount]

• Next week I'll arrive on Monday and leave on Sunday.
• I will leave on Sunday morning.
• the Sunday newspaper
• a Sunday brunch
- abbr. Sun.;
a month of Sundays
- see month
- Sundays adv
• He works Sundays. [=he works every Sunday]