what's the word?

[shabani]

What's the word for the feeling of shock that happens when you're just about to go to sleep, usually dreaming about falling off,or tripping that coincides with waking up suddenly?

 

[Linguist__]

The medical term for it is 'sleep myoclonus'. It refers to the contraction of muscles that makes you 'jump' rather than any 'feeling' that you get. I'm not sure if you are looking for a less medical word, but that's all I know.

Outside of a disease/condition, it usually occurs as a reaction to some stimulus. Watching a horror film and jumping at a scary part, for example. In the case of sleep, it happens in the early stages of the sleep cycle, normally just before you actually fall asleep and it is also a reaction to a stimulus. The stimulus could be external - something happening in the room as you are falling asleep, or it could be internal - something happening in your dream.

 

[bhaisahab]

What's the word for the feeling of shock that happens when you're just about to go to sleep, usually dreaming about falling off,or tripping that coincides with waking up suddenly?

If you are looking for a non-medical term, have a look at this link: start - Definition of start noun (SUDDEN MOVEMENT) from Cambridge Dictionary Online: Free English Dictionary and Thesaurus

 

[Raymott]

What's the word for the feeling of shock that happens when you're just about to go to sleep, usually dreaming about falling off,or tripping that coincides with waking up suddenly?

The common term is a 'myoclonic jerk'.

 

[Linguist__]

The common term is a 'myoclonic jerk'.

That's a good example of people taking a word and making it redundant. 'Myoclonic jerk' = 'myo' - muscle + 'clonus' - muscle 'twitching' + 'jerk'. So, 'Muscle muscle twitch jerk'! People should pick!

A similar example is the frequent use of 'PIN number'. Despite the fact the 'N' in 'PIN' is 'number - 'personal identification number number'.

 

[Raymott]

That's a good example of people taking a word and making it redundant. 'Myoclonic jerk' = 'myo' - muscle + 'clonus' - muscle 'twitching' + 'jerk'. So, 'Muscle muscle twitch jerk'! People should pick!

A similar example is the frequent use of 'PIN number'. Despite the fact the 'N' in 'PIN' is 'number - 'personal identification number number'.

Perhaps, but that's what it's called commonly by doctors and patients in Australia.
(Yes, and ATM Machine). But I think that's what the O.P. was asking.
I can't see where you got the second 'muscle' from though, unless you're claiming that 'myoclonic' is already redundant.
Perhaps you were perseverating.