顕著

1. Origins, structure, and basic meaning

• Structure: The adjectival noun 顕著 (けんちょ) describes a change or difference that is clearly noticeable and pronounced.
• Basic usage: It modifies a noun in 顕著な上達 or serves as a predicate in 差が顕著だった.

2. Common pitfalls and similar expressions

• A clearly noticeable degree
  • It means not just that a difference exists, but that its degree is pronounced and readily observed.