horizontal

adjective

hor·​i·​zon·​tal ˌhȯr-ə-ˈzän-tᵊl 

ˌhär-

1

a

: of or relating to the apparent junction of earth and sky : situated near the horizon

b

: parallel to, in the plane of, or operating in a plane parallel to the horizon or to a baseline : level

horizontal distance

a horizontal engine

2

: relating to, directed toward, or consisting of individuals or entities of similar status or on the same level

horizontal mergers

horizontal hostility

3

medical : relating to or being transmission (as of a disease) by physical contact or proximity in contrast with inheritance

Genes are normally inherited from parents, but they can also be inserted into a genome by viruses, plasmids, and other foreign agents—a phenomenon called horizontal transfer.

—Stephan Reebs

compare vertical sense 4

horizontal noun

horizontality

ˌhȯr-ə-ˌzän-ˈta-lə-tē 

ˌhär-

noun

horizontally

ˌhȯr-ə-ˈzän-tᵊl-ē 

ˌhär-

adverb

Examples of horizontal in a Sentence

Recent Examples on the Web

Another display Lynn created was carving out a bookcase in a couple of walls with kid-friendly map wallpaper in the back, and adding horizontal rods at the front of each shelf so the books could be displayed forward facing without falling to the floor. —Caron Golden, San Diego Union-Tribune, 8 Feb. 2025

The zones colored in darker red indicate a faster downslope movement; the arrows represent the direction of horizontal motion; the white lines show the boundaries of the active landslide area as defined by the California Geological Survey in 2007. —Kristan Hawkins, Newsweek, 7 Feb. 2025

Firefighter Jason Shoemaker of FDNY Rescue 4 used a bandsaw to cut through three vertical bars and the horizontal top piece of the fence — preventing further injury by carefully keeping the sections intact to transport the boy and fence together to the hospital. —Elizabeth Keogh, New York Daily News, 5 Feb. 2025

Per Next Gen Stats, Nix ranked 23rd in air yards per attempt (7.7) and 26th in tight window throws (13.1%). Payton, and by proxy Nix, can fall in love with the horizontal attack. —Troy Renck, The Denver Post, 13 Jan. 2025

Word History

Etymology

see horizon

First Known Use

1555, in the meaning defined at sense 1a

Phrases Containing horizontal

• horizontal bar

Kids Definition

horizontal

1 of 2 adjective

hor·​i·​zon·​tal

ˌhȯr-ə-ˈzänt-ᵊl,

ˌhär-

1

: of or relating to the horizon

2

: parallel to the horizon : level

3

: being on the same level

horizontally

-ᵊl-ē

adverb

horizontal

2 of 2 noun

: a horizontal line or plane

Medical Definition

horizontal

adjective

hor·​i·​zon·​tal ˌhȯr-ə-ˈzänt-ᵊl, ˌhär- 

1

: relating to or being a transverse plane or section of the body

2

a

: relating to or being transmission (as of a disease) by physical contact or proximity in contrast with inheritance compare vertical

b

: of or relating to horizontal gene transfer

horizontally

-ᵊl-ē 

adverb

Legal Definition

horizontal

adjective

hor·​i·​zon·​tal ˌhȯr-ə-ˈzän-təl, ˌhär- 

: relating to, directed toward, or consisting of individuals or entities of similar status or on the same level

horizontally adverb