Emily Dickinson Lexicon

CON-JEC'TURE, n. [L. conjectura; Fr. conjecture; It. congettura, or conghiettura; Sp. conjetura; Port. conjectura, or, conjeitura. See Conjecto.]

1. Literally, a casting or throwing together of possible or probable events; or a casting of the mind to something future, or something past but unknown; a guess, formed on a supposed possibility or probability of a fact, or on slight evidence; preponderance of opinion without proof; surmise. We speak of future or unknown things by conjecture, and of probable or unfounded conjectures.
2. Idea; notion. – Shak.