| 1. | Baseball. the area between bases within which a base runner must keep when running from one base to another. |
| 2. | Tennis. the line at each end of a tennis court, parallel to the net, that marks the in-bounds limit of play. |
| 3. | (in perspective drawing) a horizontal line in the immediate foreground formed by the intersection of the ground plane and the picture plane. |
| 4. | a basic standard or level; guideline: to establish a baseline for future studies. |
| 5. | a specific value or values that can serve as a comparison or control. |
| 6. | Typography. the imaginary line on which the bottoms of primary letters align. |
| 7. | Surveying. See under triangulation (def. 1). |
| 8. | Electronics. a horizontal or vertical line formed on the face of a cathode-ray tube by the sweep of the scanning dot. |
| 9. | Naval Architecture. a line on the body plan or sheer plan of a hull, representing a horizontal reference plane for vertical dimensions. |
| 10. | basic or essential. |
noun, adjective, verb, based, bas⋅ing.| 1. | the bottom support of anything; that on which a thing stands or rests: a metal base for the table. |
| 2. | a fundamental principle or groundwork; foundation; basis: the base of needed reforms. |
| 3. | the bottom layer or coating, as of makeup or paint. |
| 4. | Architecture.
|
| 5. | Botany, Zoology.
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| 6. | the principal element or ingredient of anything, considered as its fundamental part: face cream with a lanolin base; paint with a lead base. |
| 7. | that from which a commencement, as of action or reckoning, is made; a starting point or point of departure. |
| 8. | Baseball.
|
| 9. | a starting line or point for runners, racing cars, etc. |
| 10. | (in hockey and other games) the goal. |
| 11. | Military.
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| 12. | Geometry. the line or surface forming the part of a figure that is most nearly horizontal or on which it is supposed to stand. |
| 13. | Mathematics.
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| 14. | Also called base line. Surveying. See under triangulation (def. 1). |
| 15. | Painting.
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| 16. | Photography. a thin, flexible layer of cellulose triacetate or similar material that holds the light-sensitive film emulsion and other coatings, esp. on motion-picture film. |
| 17. | Chemistry.
|
| 18. | Grammar. the part of a complex word, consisting of one or more morphemes, to which derivational or inflectional affixes may be added, as want in unwanted or biolog- in biological. Compare root 1 (def. 11), stem 1 (def. 16). |
| 19. | Linguistics. the component of a generative grammar containing the lexicon and phrase-structure rules that generate the deep structure of sentences. |
| 20. | Electronics.
|
| 21. | Stock Exchange. the level at which a security ceases a decline in price. |
| 22. | Heraldry. the lower part of an escutcheon. |
| 23. | bases, Armor. a tonlet formed of two shaped steel plates assembled side by side. |
| 24. | Jewelry. pavilion (def. 6). |
| 25. | in base, Heraldry. in the lower part of an escutcheon. |
| 26. | serving as or forming a base: The walls will need a base coat and two finishing coats. |
| 27. | to make or form a base or foundation for. |
| 28. | to establish, as a fact or conclusion (usually fol. by on or upon): He based his assumption of her guilt on the fact that she had no alibi. |
| 29. | to place or establish on a base or basis; ground; found (usually fol. by on or upon): Our plan is based on a rising economy. |
| 30. | to station, place, or situate (usually fol. by at or on): He is based at Fort Benning. The squadron is based on a carrier. |
| 31. | to have a basis; be based (usually fol. by on or upon): Fluctuating prices usually base on a fickle public's demand. |
| 32. | to have or maintain a base: I believe they had based on Greenland at one time. |
| 33. | get to first base. first base (def. 2). |
| 34. | off base,
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| 35. | on base, Baseball. having reached a base or bases: Two men are on base. |
| 36. | touch base with, to make contact with: They've touched base with every political group on campus. |
n]
| 1. | a technique for establishing the distance between any two points, or the relative position of two or more points, by using such points as vertices of a triangle or series of triangles, such that each triangle has a side of known or measurable length (base or base line) that permits the size of the angles of the triangle and the length of its other two sides to be established by observations taken either upon or from the two ends of the base line. |
| 2. | the triangles thus formed and measured. |

| base line or base·line (bās'līn') n.
|
Any of a number of bitter-tasting, caustic materials. Technically, a material that produces negative ions in solution. A base is the opposite of an acid and has a pH of 7 to 14. A given amount of a base added to the same amount of an acid neutralizes the acid; water and a salt are produced. Alkalis are bases; ammonia is a common base.
base
|
base (bās)
n.
The part of an organ nearest its point of attachment.
A fundamental ingredient; a chief constituent of a mixture.
Any of a large class of compounds, including the hydroxides and oxides of metals, having a bitter taste, a slippery solution, the capacity to turn litmus blue, and to react with acids to form salts.
A molecular or ionic substance capable of combining with a proton to form a new substance. Also called Brønsted base.
A nitrogen-containing organic compound that combines in such a manner.
A substance that provides a pair of electrons for a covalent bond with an acid.
base line n.
A line corresponding to the base of the skull, passing from the infraorbital ridge to the midline of the occiput, through the ear canal.
A line serving as a basis, as for measurement or calculation.