There is currently no such status as "associate member" defined in the EU treates although the idea of special status for not being a complete member was floating around for a while now.
Just calling it a "unique alliance" or "deepening of their relationship" wouldn't have had such a public effect.
Half of the right wing influencers on X is going bananas because when the US was "offering" Canada to join them, they said a firm "NO" but for the EU they are opening the door.
Trump even said when the Canada joins the EU as associate member, it could be considered a hostile act.
All that for a status nobody knows yet what it will entail. More than a simple trade deal, for sure, but also a lot less than a proper membership.