Some office supply websites call them 'mechanical pencils', Merghan, but I've never heard anyone use that term in real life.
I don't think there's anything better than propelling pencil - formal or informal.
Rover
1. Is "lead pencil" a right synonym?
2. Would you please give me some collocations used with it? For example, should I say, 'I've run out of lead!':?: 'My lead's run out' would be much better', 'Have you got an[STRIKE]y[/STRIKE] extra lead*?', 'I need to change the lead':tick:, or, 'My lead pencil takes 0.7 leads.':tick:?
:down: A standard old pencil is a lead pencil.
* Note that - as in your last example - 'a lead' is countable in this case.
I like NZ's 'clutch pencil', but it doesn't work in Br. English.
b