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"
a piece of land prepared for playing a game; "the home crowd cheered when Princeton took the field"
the circumstances under which competition occurs; "the government's objective is to insure a genuinely level playing field for American industry and commerce in Europe"