"rain" vs "rainfall"

[Nessie]

Hi,

I know that "rainfall" has the meaning of "the total amount of rain that falls in a particular area in a particular amount of time", but I just wonder if it can be used to mean a rain. I saw this in a dictionary (I don't know its name. It's a monolingual dictionary for mobile phones).

Cloudburst: a heavy and sudden rainfall

And when I looked it up in the OALD, I found this:

rainfall
noun
[U, sing.] the total amount of rain that falls in a particular area in a particular amount of time; an occasion when rain falls: There has been below average rainfall this month. ◆ an average annual rainfall of 10 cm

Is the bold part implies the word's meaning as a rain? If not, could you plesae make a sentence to clarify it? If yes, I just wonder why they don't consider it as a second meaning instead of using a ";"

Many thanks
Nessie
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[Yankee]

Hi Nessie

I'd say that, although there are times when the words 'rain' and 'rainfall' are used as countable nouns, they are both more often used uncountably.
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[Nessie]

Thanks a lot, Amy

But... I'm asking about the meaning of "rainfall" as "rain", not its usage as a countable noun... :O
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[Yankee]

Do you mean something like this?

- The rainfall last night caused substantial flooding.
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[Nessie]

Yes, Amy. Does it mean exactly the same as "The rain last night caused substantial flooding."?


_________________
... something we never have again, I know... I guess I really really know..

Sorry seems to be the hardest word...

[Yankee]

Hi Nessie

The use of rainfall sounds more formal.
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[Nessie]

Oh, I got it now. Thanks a lot, Amy

It's so nice to be online at the same time as you like this , but I have to go to bed now since it's nearly 2 a.m. now
(Sleepyyy... I am so sleepyyyy... )

Goodnight to you, Amy!
_________________
... something we never have again, I know... I guess I really really know..

Sorry seems to be the hardest word...

[Inga]

I always thought 'rainfall' has one more meaning: 'Heavy rain'. And if we say 'light rainfall' it means the rain was heavy but short. Isn't it true?
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[Nessie]

I have no idea whether it's true or not but I just find no such meaning for the word in any dictionaries
_________________
... something we never have again, I know... I guess I really really know..

Sorry seems to be the hardest word...

[Yankee]

The word 'rainfall' doesn't necessarily suggest 'heavy rain' to me.
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