Vancouver is a 'numeric' referencing style often used in medicine and science disciplines.
Below are two guides to different versions of 'Vancouver' referencing.
The authoritative source for Vancouver referencing is Citing medicine: the NLM style guide for authors (see Section N: Vancouver referencing style in Pears R, Shields, G. Cite them right. 12th ed. London: Bloomsbury Academic; 2022).
However, in a broad sense, other numeric systems may be referred to as 'Vancouver'.