1

semi

play
noun \ˈse-mē also -ˌmī\

Definition of semi

plural

semis

chiefly British

  1. :  a semidetached house

Origin and Etymology of semi

short for semidetached


First Known Use: 1912


2

semi

play
noun \ˈse-ˌmī also -mē\

Definition of semi

plural

semis

1942

First Known Use of semi

1942

Other Automotive Terms


3

semi

play
noun \same as 2semi\

Definition of semi

plural

semis

  1. :  semifinal —often used in plural

1942

First Known Use of semi

1942


semi-

prefix \ˌse-mē, -ˌmī, -mi\

Definition of semi-

  1. 1a :  precisely half of: (1) :  forming a bisection of semidiameter (2) :  being a usually vertically bisected form of (a specified architectural feature) semidomeb :  half in quantity or value :  half of or occurring halfway through a specified period of time semiannual semimonthly — compare bi-

  2. 2 :  to some extent :  partly :  incompletely semicivilized semi-independent semidry — compare demi-, hemi-

  3. 3a :  partial :  incomplete semiconsciousness semidarknessb :  having some of the characteristics of semiporcelainc :  quasi- semigovernmental semimonastic

Origin and Etymology of semi-

Middle English, from Latin; akin to Old High German sāmi- half, Greek hēmi-


SEMI Defined for English Language Learners

semi-

prefix

Definition of semi- for English Language Learners

  • : half

  • : happening twice during a particular period of time

  • : partly : not completely


SEMI- Defined for Kids

semi-

prefix

Definition of semi- for Students

  1. 1 :  half semicircle

  2. 2 :  partly :  not completely

  3. 3 :  partial



Seen and Heard

What made you want to look up semi? Please tell us where you read or heard it (including the quote, if possible).

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

WORD OF THE DAY

a lively discussion

Get Word of the Day daily email!

WORD GAMES

Take a 3-minute break and test your skills!

  • istock-refers-to-this-as-a-tumble-of-strawberries-which-sounded-pretty-nice-to-us
  • Which is a synonym of garner?
Spell It

Can you spell these 10 commonly misspelled words?

TAKE THE QUIZ
Word Winder's CrossWinder

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!