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line 1 (līn)
1. Mathematics A geometric object with neither width nor depth, typically straight and extending indefinitely.
a. A thin continuous mark, as that made by a pen, pencil, or brush applied to a surface.
b. A similar mark cut or scratched into a surface.
c. A crease in the skin, especially on the face; a wrinkle.
a. A real or imaginary mark positioned in relation to fixed points of reference.
b. A degree or circle of longitude or latitude drawn on a map or globe.
c. The equator. Used with the.
a. A border or boundary: the county line.
b. A demarcation: a line of darker water beyond the reef.
c. A contour or an outline: the line of the hills against the evening sky.
a. A mark used to define a shape or represent a contour.
b. Any of the marks that make up the formal design of a picture.
a. A cable, rope, string, cord, or wire.
b. Nautical A rope used aboard a ship.
c. A fishing line.
d. A clothesline.
e. A cord or tape used, as by builders or surveyors, for measuring, leveling, or straightening.
7. A pipe or system of pipes for conveying a fluid: gas lines.
8. An electric-power transmission cable.
a. A wire or system of wires connecting telephone or telegraph systems.
b. An open or functioning telephone connection: tried to get a free line.
a. A passenger or cargo system of public or private transportation, as by ship, aircraft, or bus, usually over a definite route.
b. A company owning or managing such a system.
a. A railway track or system of tracks.
b. A particular section of a railway network: the Philadelphia-Trenton line.
12. A course of progress or movement; a route: a line of flight.
a. A general method, manner, or course of procedure: different lines of thought; took a hard line on defense.
b. A manner or course of procedure determined by a specified factor: development along socialist lines.
c. An official or prescribed policy: the party line.
14. often lines A general concept or model: a trilogy along the lines of the Oresteia.
a. The condition of being in proper or aligned position: Is the table in line with the sofa?
b. A condition of agreement or correspondence: Your attitude is in line with mine. Is the policy in line with reality?
a. One's trade, occupation, or field of interest: What line of work are you in?
b. Range of competence: not in my line.
17. Merchandise or services of a similar or related nature: carries a complete line of small tools.
18. A group of persons or things arranged in a row or series: long lines at the box office; a line of stones.
a. Ancestry or lineage.
b. A series of persons, especially from one family, who succeed each other: a line of monarchs; comes from a long line of bankers.
c. A strain, as of livestock or plants, developed and maintained by selective breeding.
a. A sequence of related things that leads to a certain ending: a line of argument.
b. An ordered system of operations that allows a sequential manufacture or assembly of goods at all or various stages of production.
c. The personnel of an organization or a business who actually make a product or perform a service.
21. A horizontal row of printed or written words or symbols.
22. One of the horizontal scans forming a television image.
23. A brief letter; a note: I'll drop you a line.
a. A unit of verse ending in a visual or typographic break and generally characterized by its length and meter: a line of iambic pentameter.
b. A unit of uninterrupted text spoken by an actor: spent the weekend learning her lines.
25. Informal Glib or insincere talk, usually intended to deceive or impress: He kept on handing me a line about how busy he is.
26. lines Chiefly British
a. A marriage certificate.
b. A usually specified number of lines of prose or verse to be written out by a pupil as punishment.
27. Games A horizontal demarcation on a scorecard in bridge dividing the honor score from the trick score.
a. A source of information.
b. The information itself: got a line on the computer project.
a. Music One of the five parallel marks constituting a staff.
b. A sustained melodic or harmonic part in a piece: strained to hear the tenor line.
a. A formation in which elements, such as troops, tanks, or ships, are arranged abreast of one another.
b. The battle area closest to the enemy; the front.
c. The combat troops or warships at the front, arrayed for defense or offense.
d. The regular forces of an army or a navy, in contrast to staff and support personnel.
e. The class of officers in direct command of warships or of army combat units.
f. A bulwark or trench.
g. An extended system of such fortifications or defenses: the Siegfried line.
31. Sports
a. A foul line.
b. A real or imaginary mark demarcating a specified section of a playing area or field.
c. A real or imaginary mark or point at which a race begins or ends.
d. The center and two wings making up a hockey team's offensive unit.
e. Football A line of scrimmage.
f. Football The linemen considered as a group.
32. Informal The odds a bookmaker gives, especially for sports events.
33. The proportion of an insurance risk assumed by a particular underwriter or company.
34. Slang An amount of powdered cocaine arranged in a thin, long strip for snorting.
v. lined, lin·ing, lines
v. tr.
1. To mark, incise, or cover with a line or lines.
2. To represent with lines.
3. To place in a series or row.
4. To form a bordering line along: Small stalls lined the alley.
5. Baseball To hit (a ball) sharply so that it flies low and fast.
v. intr.
To hit a line drive: lined out to shortstop.
Phrasal Verb:
line up
1. To arrange in or form a line.
2. Football To take one's position in a formation before a snap or kickoff.
3. To organize or make ready: lined up considerable support for the bill.
4. To engage or schedule: lined up some freelance work for next month; lined up a speaker for graduation.
all along the line
1. In every place.
2. At every stage or moment.
down the line
1. All the way; throughout: Errors are to be found down the line.
2. At a point or an end in the future.
in line for
Next in order for: in line for the presidency.
on the line
1. Ready or available for immediate payment.
2. So as to be risked; in jeopardy: “Careers were on the line once again” (Seymour M. Hersh).
out of line
1. Uncalled-for; improper.
2. Unruly and out of control.

[Middle English, from Old English līne and from Old French ligne, both from Latin līnea, string, cord, from feminine of līneus, of linen, from līnum, thread, linen; see lno- in the Appendix of Indo-European roots.]

The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. All rights reserved.
line 2 (līn)
tr.v. lined, lin·ing, lines
1. To fit a covering to the inside surface of: a coat lined with fur.
2. To cover the inner surface of: Moisture lined the walls of the cave.
3. To fill plentifully, as with money or food.
line (one's) pockets
To make a profit, especially by illegitimate means.

[Middle English linen, from line, flax, linen cloth, from Old English līn, from Latin līnum; see lno- in the Appendix of Indo-European roots.]

The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. All rights reserved.

Indo-European & Semitic Roots Appendices

    Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:

    Indo-European Roots

    Semitic Roots

    The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.