"Half-Hollowfication Ichigo".
Recently, in an interview of Kubo-sensei published in the "Weekly Shonen Jump" it was reveled that the "hollowfied form" which Ichigo dawned against "Soul King Yhwach", popularly known as "Horn of Salvation (HoS) Ichigo" among the fans, based on the name of "chapter 676" of the manga in which the form was first revealed will be officially named as "Half-Hollowfication Ichigo".
Weekly Shonen Jump translation :-
最終決戦となる最終クールのティザービジュアルは“半虚化一護”
The teaser visual for the final cour, which will be the ultimate showdown, features "Half-Hollowfication Ichigo".
【半虚化一護】とは･･･
About "Half-Hollowfication Ichigo".
一護がユーハバッハと対峙した際に見せた形態。作中で名称が明らかになっていなかったが、久保先生が禍進譚制作時に名付けられた。その名は“半虚化一護”。
This is the form Ichigo displayed when facing Yhwach. Although it was never officially named in the series, Kubo-sensei gave it the title "Half-Hollowfication Ichigo" during the production of "The Conflict".
My opinion :-
Since- "半" refers to something that is incomplete, something "Half" or "Partial". Imo Kubo sensei is not just calling HoS a "Half" transformation but he also mean it as a "Partial" one, since "Half" is a strong word which closes options for further multiple powerups except a "Full" transformation, while "Partial" is more of a flexible term that explains HoS better, as in Ichigo gets Partially Hollowfied by using Yhwach's power as a catalyst since he doesn't have control over his hollow powers yet and it leaves the option for Ichigo taking a controlled "Half" form on his own or "Complete" Hollowfication form similar to FH Ichigo with "two horn" in future adaptation of the manga.
A fan-art on how Full-Hollowfication Ichigo would look like imo:-
