an obstruction that stands in the way (and must be removed or surmounted or circumvented)
something immaterial that stands in the way and must be circumvented or surmounted; "lack of imagination is an obstacle to one's advancement"; "the poverty of a district is an obstacle to good education"; "the filibuster was a major obstruction to the success of their plan"
the act of referring or consulting; "reference to an encyclopedia produced the answer"
the most direct or specific meaning of a word or expression; the class of objects that an expression refers to; "the extension of `satellite of Mars' is the set containing only Demos and Phobos"
the relation between a word or phrase and the object or idea it refers to; "he argued that reference is a consequence of conditioned reflexes"
a publication (or a passage from a publication) that is referred to; "he carried an armful of references back to his desk"; "he spent hours looking for the source of that quotation"
the power or right to prohibit or reject a proposed or intended act (especially the power of a chief executive to reject a bill passed by the legislature)
vote against; refuse to endorse; refuse to assent; "The President vetoed the bill"