noun
first issue; first number; the first
Used for the first issue of a magazine, series, or numbered publication. Can also refer to the first item in a numbered list or the first of something in a sequence.
この雑誌の第一号は1980年に発行された。
The first issue of this magazine was published in 1980.
第一号の切符を買うことができた。
I was able to buy the first ticket (ticket number one).
創刊号 specifically means 'first issue' of a newly launched publication, emphasizing the inaugural nature.
Compound of 第一 (first) and 号 (number/issue).