"These large clouds worry us."

Translation: Ces gros nuages nous inquiètent.

[Anneduol1ngo]

Ok, so I have learned that 'grand' is for big in height and 'gros' is for big in width but why are these clouds 'gros' not 'grands'? I would suggest that a tall thunder cloud is much more concerning than a general cover of cloud.

Can someone explain why 'grands' is incorrect here please?

[n6zs]

There are several words that mean "big" but have slightly different versions in French:

• grand : general term for "big" but used to mean "tall" with people
• gros : "big" in terms of being thick or fat (this is the adjective of choice when referring to a cloud).
• large : "big" in terms of width, e.g., a street, a river, etc.

[Anneduol1ngo]

Thanks. So it seems that it is just convention.