horizontal

[ hawr-uh-zon-tl, hor- ]

adjective

1. at right angles to the vertical; parallel to level ground.
2. flat or level:

   a horizontal position.

3. being in a prone or supine position; recumbent:

   His bad back has kept him horizontal for a week.

4. near, on, or parallel to the horizon.
5. of or relating to the horizon.
6. measured or contained in a plane parallel to the horizon:

   a horizontal distance.

7. (of material on a printed page, pieces on a game board, etc.) extending across, from the left to the right of the viewer.
8. of or relating to a position or individual of similar status:

   He received a horizontal promotion to a different department, retaining his old salary and title.

9. Economics. of or relating to companies, affiliates, divisions, etc., that perform the same or similar functions or produce the same or similar products:

   Through horizontal mergers the company monopolized its field.

noun

1. anything horizontal, as a plane, direction, or object.

horizontal

/ ˌhɒrɪˈzɒntəl /

adjective

1. parallel to the plane of the horizon; level; flat Compare vertical
2. of or relating to the horizon
3. measured or contained in a plane parallel to that of the horizon
4. applied uniformly or equally to all members of a group
5. economics relating to identical stages of commercial activity

   horizontal integration

noun

1. a horizontal plane, position, line, etc

Derived Forms

• ˌhorizonˈtality, noun
• ˌhoriˈzontally, adverb

Other Words From

• hor·i·zon·tal·i·ty [hawr-i-zon-, tal, -i-tee, hor-], hori·zontal·ness noun
• hori·zontal·ly adverb
• subhor·i·zontal adjective
• subhor·i·zontal·ly adverb
• subhor·i·zontal·ness noun
• unhor·i·zontal adjective
• unhor·i·zontal·ly adverb

Word History and Origins

Origin of horizontal¹

1545–55; < Latin horizont- (stem of horizōn ) horizon + -al ¹

Example Sentences

Now, in bacteria — which are a type of prokaryote, or single-celled organism — a lot of evolution happens by horizontal gene transfer.

From Salon

This isn’t necessarily good for us, though: antibiotic resistance has become a massive problem in large part due to horizontal transfer of genes from drug-resistant species into bacteria species that were once routinely killed by medications.

From Salon

To simplify a bit, if Bacteria A acquires gene 1 by horizontal transfer and also acquires gene 2, and then we notice that Bacteria B has also acquired gene 1, we might correctly predict that Bacteria B has gene 2 as well — because in this scenario, genes 1 and 2 tend to stick together in a genome.

From Salon

What this means is that evolution in E. coli, despite the serendipity of horizontal gene transfer, isn’t just a matter of chance.

From Salon

Around her living room, miniature dioramas of crucial moments in Black American history took up much of the horizontal space.

From Los Angeles Times