Why do algorithms text book uses "nondecreasing" instead of "increasing" to mention sorted array?

Question

Is there any particular reason? or it's just the preference of author? For example here's the Kruskal algorithm from CLRS:

Answer 1

Nondecreasing means that the values could stay the same - they don't decrease but they could increase or stay the same.

The values 1, 1, 1, 2 are in nondecreasing order but 1, 2, 3, 4 are increasing.