To triple vs to treble; a verb for 'make thrice as less'

[Tamara]

Hi

What verb do you prefer to use for 'to make something three times more' (in amount)?
to triple?
to treble?

Could you also say, is there a verb in English with the meaning 'make something three times less'?
Or should I build an expression with thrice or threefold or something like that, - and with 'less'?
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It’s impossible to learn swimming without entering the water…

[Mister Micawber]

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I like treble, but I think it is fading away (as is thrice); I use triple (quadruple, quintuple, etc).

We can halve and quarter things, but I have never heard a verb for other fractions. I suggest you avoid trying to get fancy with '-fold', which is a multiple suffix, and state it forthrightly: we made it / reduced it to one-third the size.
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Native English teacher at Mister Micawber's

[Tamara]

Thank you, Mister Micawber.