Straight, a. [Compar. Straighter superl. Straightest.]
 1. Right, in a mathematical sense; passing from one point to another by the nearest course; direct; not deviating or crooked; as, a straight line or course; a straight piece of timber.
    And the crooked shall be made straight.   --Isa. xl. 4.
    There are many several sorts of crooked lines, but there is only one which is straight.   --Dryden.
 2. Bot. Approximately straight; not much curved; as, straight ribs are such as pass from the base of a leaf to the apex, with a small curve.
 3. Card Playing Composed of cards which constitute a regular sequence, as the ace, king, queen, jack, and ten-spot; as, a straight hand; a straight flush.
 4. Conforming to justice and rectitude; not deviating from truth or fairness; upright; as, straight dealing.
 5. Unmixed; undiluted; as, to take liquor straight. [Slang]
 6. Making no exceptions or deviations in one's support of the organization and candidates of a political party; as, a straight Republican; a straight Democrat; also, containing the names of all the regularly nominated candidates of a party and no others; as, a straight ballot. [Political Cant, U.S.]
 Straight arch Arch., a form of arch in which the intrados is straight, but with its joints drawn radially, as in a common arch.
 A straight face, one giving no evidence of merriment or other emotion.
 A straight line. “That which lies evenly between its extreme points.” --Euclid. “The shortest line between two points.” --Chauvenet. “A line which has the same direction through its whole length.” --Newcomb.
 Straight-way valve, a valve which, when opened widely, affords a straight passageway, as for water.