Reckoner - (rek-en-ur) - n. singular - definitions:
1. a handbook or calculating machine used in mathematics. 2. a) an expert at calculation; b) a judge, arbiter, or other decision-maker esp. in justice, logic, rhetoric, governance. c) the "voice of moderation" [colloquial]. 3. A journal containing the thoughts and opinions of a rational mind on matters pertaining to politics, society, religion, and culture, both past and present.