na-adjective, noun
well-known; renowned; name recognition
A Sino-Japanese noun or na-adjective meaning that a person, organization, work, etc. is known by name. It is more written or formal than everyday 有名, and the noun use often appears in phrases such as 知名を得る.
彼はその小説で一躍知名を得た。
He gained sudden recognition through that novel.
彼女は国際的に知名なデザイナーだ。
She is an internationally well-known designer.
Means 'degree of name recognition' and is the common noun used when saying recognition is high or low, as in 知名度が高い.
Sino-Japanese compound written with 知 'know' and 名 'name'; the spelling transparently conveys the idea of a name being known. This is a component explanation, not a detailed historical derivation.