Here is another source, and despite this being in Wikipedia it gives you the references at the end.
https://en.wikipedia.org/wiki/Website_wireframe
A website wireframe, also known as a page schematic or screen
blueprint, is a visual guide that represents the skeletal framework of
a website. Wireframes are created for the purpose of arranging
elements to best accomplish a particular purpose. The purpose is
usually being informed by a business objective and a creative idea.
The wireframe depicts the page layout or arrangement of the website’s
content, including interface elements and navigational systems, and
how they work together. The wireframe usually lacks typographic
style, color, or graphics, since the main focus lies in functionality,
behavior, and priority of content. In other words, it focuses
on what a screen does, not what it looks like.
Because it is synonymous with blueprint, you could go much further back into the past to when the blueprint first arrived in architecture.
Another source is this blog, which attempts to show the history:
http://www.infragistics.com/community/blogs/devtoolsguy/archive/2015/08/13/the-history-of-wireframing-amp-prototyping.aspx
The term wireframe actually predates its use in web design.
Originally, wireframes were used to show 3D objects in Computer Aided
Design (CAD). You’d probably recognize the style, used in
manufacturing to depict the design of cars without the need for
detail, leaving the drawing looking like it's made out of wires -
hence, you guessed it, the term ‘wireframe’.
This quote is also on the Wikipedia page, which is where Infragistics got this from.