to carry the sense

[GoldfishLord]

momentous (adj.)​
"of moment or consequence, critical, of surpassing importance," 1650s, from moment + -ous to carry the sense of "important" while momentary kept the meaning "of an instant of time." Related: Momentously; momentousness.​
(Retrieved from https://www.etymonline.com/word/momentous#etymonline_v_31375 )
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I'm not sure if "to" is used there to show the purpose or to show the result.

I'd like to know what your opinion is about that.

 

[emsr2d2]

I would say it's for purpose.

-ous is used in order to carry the sense of importance.

 

[GoldfishLord]

momentous (adj.)​
"of moment or consequence, critical, of surpassing importance," 1650s, from moment + -ous to carry the sense of "important" while momentary kept the meaning "of an instant of time.
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I'd also like to know if the green part modifies "-ous" but not "from moment +".

 

[emsr2d2]

Yes. It doesn't apply simply to "momentous". The suffix -ous is generally used for the same purpose.

 

[jutfrank]

I don't think the green part is in reference to the suffix -ous.

The suffix -ous usually means something like 'full of', so momentous means something like 'full of moment'. The green part is saying that this is similar in meaning to important.

 

[Tdol]

Given that importance occurs earlier in the definition, and it says from moment +, I can't see how it only applies to the suffix.