I. af‧ter‧noon¹ S1 W2 /ˌɑːftəˈnuːn◂ $ ˌæftər-/ noun [uncountable and countable]

1. the part of the day after the morning and before the evening ⇒ morning, evening:
There’s a meeting on Thursday afternoon.
It was very hot in the afternoon.
See you tomorrow afternoon.
Are you going into town this afternoon?
We met in the early afternoon.
By late afternoon, Micky had changed his mind.
He was having his afternoon nap.

2. afternoons during the afternoon every day:
She only works afternoons.

[TahlilGaran] Dictionary of Contemporary English ▲

II. afternoon² interjection British English informal
used to greet someone when you meet them in the afternoon

[TahlilGaran] Dictionary of Contemporary English ▲

afternoon
noun
ADJ. this, tomorrow, yesterday | Friday, Saturday, etc. | early, late | April, May, etc. | spring, summer, etc. | long the long sunny afternoons
golden, hot, sunny, warm | grey, rainy, wet
VERB + AFTERNOON spend We spent the afternoon sitting by the pool.
AFTERNOON + VERB progress, wear on As the afternoon wore on he began to look unhappy.
AFTERNOON + NOUN tea Afternoon tea is served on the terrace.
light, sun The afternoon sun shone full on her.
PREP. by ~, during the ~, in the ~, on Monday, etc. ~
PHRASES an/the afternoon off You deserve an afternoon off.

[TahlilGaran] Collocations Dictionary ▲

afternoon

Monday/Friday/Saturday etc afternoon
Did you see the football on Saturday afternoon?
this afternoon (=today in the afternoon)
I'll come round to your house this afternoon.
early/late afternoon
I arrived in Boston in the early afternoon.
all afternoon/the whole afternoon
You left the lights on all afternoon.
tomorrow afternoon
What are you doing tomorrow afternoon?
yesterday afternoon
I went to see mum yesterday afternoon.
an afternoon nap (=short sleep)
Dad was having his Sunday afternoon nap.
the afternoon sun
It was too hot to go out in the afternoon sun.
afternoon tea (=a light meal eaten in the afternoon with a cup of tea)
Some people still have afternoon tea at 4 o'clock.
the middle of the afternoon
It was the middle of a long hot summer afternoon.
spend the afternoon somewhere/doing something
We decided to spend the afternoon in town.

[TahlilGaran] Collocations Dictionary ▲

afternoon
noun
BAD: Afternoon we have classes until five o'clock.
GOOD: In the afternoon we have classes until five o'clock.
BAD: School finishes at five in afternoon.
GOOD: School finishes at five in the afternoon.
BAD: The afternoon I met them at the hotel and we went to the beach.
GOOD: In the afternoon I met them at the hotel and we went to the beach.

[TahlilGaran] Dictionary of Common Errors ▲