tentative title; working title
Used for a provisional title of a work (book, film, project) before the final title is decided.
新作の仮題は「春の風」です。
The working title of the new work is 'Spring Breeze'.
The editor gave the novel a tentative title.
企画書には仮題を書いておいてください。
Please write a tentative title on the project proposal.
A working title for the movie was finally settled on.
題名 is the general word for the title of a work, whereas 仮題 specifically denotes a working title used before the final one is settled.
Compound of 仮 (かり, 'temporary') and 題 (だい, 'title'). The reading かだい is a standard on'yomi combination.