old character form; kyūjitai; traditional kanji form
Refers to the traditional, pre-1946 kanji forms used in Japan, as opposed to the simplified 新字体 (shinjitai). Often used in discussions of orthography and historical texts.
See also: 新字体
學 is the kyūjitai (old form) of 学.
This book is written in old character forms, so it's hard to read.
新字体 is the modern simplified kanji form, while 旧字体 is the traditional form used before the 1946 reform.
Standard modern spelling.
Historical spelling using pre-reform kanji; it is containing out-dated kanji.
Compound of 旧 (old) + 字体 (character form). The term became common after the 1946 kanji reform to distinguish pre-reform forms from the new simplified ones.