La conception assistée par ordinateur (CAO) comprend l'ensemble des logiciels et des techniques de modélisation géométrique permettant de concevoir, de tester virtuellement – à l'aide d'un ordinateur et des techniques de simulation numérique – et de réaliser des produits manufacturés et les outils pour les fabriquer.
On confond souvent CAO et DAO (dessin assisté par ordinateur) : la CAO n'a pas pour fonction première l'édition du dessin. Il s'agit d'un outil informatique souvent lié à un métier, fonctionnant en langage dit objet, et permettant l'organisation virtuelle de fonctions techniques. Cela permet ensuite la simulation de comportement de l'objet conçu, l'édition éventuelle d'un plan ou d'un schéma étant automatique et accessoire. En DAO, un trait est un trait et le logiciel ne permet pas l'interprétation technique de l'ensemble.
https://fr.wikipedia.org/wiki/Conception_assistée_par_ordina...

Le dessin assisté par ordinateur (DAO) est une discipline permettant de produire des dessins techniques avec un logiciel informatique. On le distingue de la synthèse d'image dans la mesure où il ne s'agit pas du calcul de rendu d'un modèle numérique, mais de l'exécution de commandes graphiques (traits, formes diverses...). De ce fait, en DAO, la souris et le clavier remplacent le crayon et les autres instruments du dessinateur.
https://fr.wikipedia.org/wiki/Dessin_assisté_par_ordinateur

Unfortunately both articles (1) and (2) are linked to the following (3), which itself redirects to the 2nd one (CAD) only:

Computer-aided design (CAD) is the use of computer systems (or workstations) to aid in the creation, modification, analysis, or optimization of a design.[1] CAD software is used to increase the productivity of the designer, improve the quality of design, improve communications through documentation, and to create a database for manufacturing.[2] CAD output is often in the form of electronic files for print, machining, or other manufacturing operations. The term CADD (for Computer Aided Design and Drafting) is also used.
https://en.wikipedia.org/wiki/Computer-aided_design

We can conclude that DAO corresponds to CAD. But is CAO the 1st stage of CAD or anything else?

La CAO électronique (pour Conception assistée par ordinateur électronique) , nommée également en anglais EDA (pour Electronic design automation) , est la catégorie des outils servant à la conception et la production des systèmes électroniques allant des circuits imprimés jusqu'aux circuits intégrés.
https://fr.wikipedia.org/wiki/Conception_assistée_par_ordina...

is linked to:

Electronic design automation (EDA), also referred to as electronic computer-aided design (ECAD),[1] is a category of software tools for designing electronic systems such as integrated circuits and printed circuit boards. The tools work together in a design flow that chip designers use to design and analyze entire semiconductor chips. Since a modern semiconductor chip can have billions of components, EDA tools are essential for their design.
https://en.wikipedia.org/wiki/Electronic_design_automation


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Note added at 5 days (2018-10-29 16:42:19 GMT)
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Up to now I thought that that the English equivalent for CAO could be found by searching Wikipedia, but found nothing than "EDA".

I now used Goggle and entered the literal translation "Computer Aided Conception"and Goggle returned a lot of hits, e.g.:

Profound skills in computer-aided methods are of growing importance for every engineer in all fields of professional activity. The four-semester programme Master of Science in Computer Aided Conception and Production in Mechanical Engineering (CAME) is designed to broaden and increase the knowledge and practical use of computer-aided simulation techniques in mechanical engineering. This programme specifically addresses the needs of the practising mechanical engineer. Its focus lies on the development and application of computer-aided methods and systems at all stages of product development, from the initial conception of machines to the manufacturing process.
https://www.daad.de/deutschland/studienangebote/internationa...

BTW: I had this idea from the very beginning (I think having heard of it some years ago), but was confused by the impossibility to retrieve it with Wikipédia. Sorry for not having googled before, but I am still on holidays and have only my smartphone with me.