horizontal

adjective

hor·​i·​zon·​tal ˌhȯr-ə-ˈzän-tᵊl How to pronounce horizontal (audio)
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 noun
horizontally adverb

Examples of horizontal in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Only his changeup has significant horizontal movement, with the righty largely working up and down to fool batters. Mitch Bannon, New York Times, 19 May 2025 Sherwood attributes this to the company’s commitment to building strong horizontal functions and trust between IT and the business. Peter High, Forbes.com, 19 May 2025 Filling a horizontal line gives you resources (wheat, wood, and stone) from that line but does not clear it. Kevin Purdy, ArsTechnica, 16 May 2025 This mouse has most of the same standout features, such as gesture controls, a horizontal scroll wheel, and a smooth-scrolling vertical wheel, and some users even prefer the scroll wheel of the 2S, which uses a physical pin to swap between smooth and ratcheted scrolling instead of a magnet. Henri Robbins, Wired News, 16 May 2025 See All Example Sentences for horizontal

Word History

Etymology

see horizon

First Known Use

1555, in the meaning defined at sense 1a

Time Traveler
The first known use of horizontal was in 1555

Cite this Entry

“Horizontal.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/horizontal. Accessed 23 May. 2025.

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- How to pronounce horizontal (audio)
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 adverb

Legal Definition

horizontal

adjective
hor·​i·​zon·​tal ˌhȯr-ə-ˈzän-təl, ˌhär- How to pronounce horizontal (audio)
: relating to, directed toward, or consisting of individuals or entities of similar status or on the same level
horizontally adverb
Last Updated: - Updated example sentences
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