noun
medium-sized dictionary
Refers to a dictionary that is neither a pocket-sized concise edition nor a large comprehensive unabridged work; often used in titles.
この中辞典は収録語数が約5万語です。
This medium-sized dictionary contains about 50,000 entries.
小辞典 is a small or concise dictionary, while 中辞典 is a medium-sized one.
Compound of 中 (medium) and 辞典 (dictionary).