- Which (of two); which one (of two); -- used
interrogatively and relatively. - In case; if; -- used to introduce the first or two or
more alternative clauses, the other or others being connected by or, or
by or whether. When the second of two alternatives is the simple
negative of the first it is sometimes only indicated by the particle
not or no after the correlative, and sometimes it is omitted entirely
as being distinctly implied in the whether of the first.