semi

¹

[ sem-ee, sem-ahy ]

noun

, Informal.

1. semitrailer ( def 1 ).
2. Often semifinal ( def 3 ).

semi-

²

1. a combining form borrowed from Latin, meaning “half,” freely prefixed to English words of any origin, now sometimes with the senses “partially,” “incompletely,” “somewhat”:

   semiautomatic; semidetached; semimonthly; semisophisticated.

semi-

¹

prefix

1. See demi-, hemi-
   half Compare demi- hemi-

   semicircle

2. partially, partly, not completely, or almost

   semifinal

   semiprofessional

3. occurring twice in a specified period of time

   semiweekly

   semiannual

semi

²

/ ˈsɛmɪ /

noun

1. a semidetached house
2. See semifinal
   short for semifinal
3. See semitrailer
   short for semitrailer

semi–

1. A prefix that means “half,” (as in semicircle, half a circle) or “partly, somewhat, less than fully,” (as in semiconscious, partly conscious).

Confusables Note

See bi- ¹.

Word History and Origins

Origin of semi¹

By shortening

Origin of semi²

Middle English < Latin sēmi-; cognate with Old English sōm-, sām- half (modern dial. sam- ), Old High German sāmi-, Sanskrit sāmi-, Greek hēmi-; sesqui-

Word History and Origins

Origin of semi¹

from Latin; compare Old English sōm-, sām- half, Greek hēmi-

Example Sentences

Here they are semi-touching at a grocery store; she likes kombucha.

From The Daily Beast

Brinsley stepped up to the passenger side of the patrol car, raised a silver Taurus semi-automatic pistol and began firing.

From The Daily Beast

Tiger Lily and her tribe, however, were outfitted in semi-realistic outfits (read: nearly naked).

From The Daily Beast

For the next hour and half I was the willing sex slave of a semi-professional Master I had met through a friend.

From The Daily Beast

After curing the elderly of their semi-suicidal depression, winning the White House must seem like a snap.

From The Daily Beast

Our troops have done all that flesh and blood can do against semi-permanent works, and they are not able to carry them.

From Project Gutenberg

The stop-keys will be seen arranged in an inclined semi-circle overhanging and just above the keyboards.

From Project Gutenberg

There are four types: bituminous (soft), anthracite (hard), semi-bituminous and semi-anthracite.

From Project Gutenberg

There were semi-savage native chiefs, and there were others, like Aguinaldo himself, with humane instincts.

From Project Gutenberg

The brilliant light of a policeman's torch sliced through the semi-darkness and spotted him.

From Project Gutenberg

Related Words

• car
• crate
• freighter
• jeep
• lorry
• pickup
• rig
• van
• wagon

Words That Use semi-

What does semi- mean?

Semi– is a combining form used like a prefix meaning “half.” In some instances, it is used figuratively to mean “partially,” “incompletely,” or “somewhat.” It is often used in a variety of technical and everyday terms.

Semi– comes from Latin sēmi-, meaning “half.” The Greek cognate of sēmi– is hēmi-, also meaning “half,” which is the source of English terms such as hemialgia and hemicardia. To learn more, check out our entries for both words.

Examples of semi-

An example of a word you may have encountered that features semi– is semicolon, “the punctuation mark (;).”

We know semi– means “half,” and a colon is the sign (:). The word colon itself comes from Greek kôlon, meaning “limb; part of a clause or period.” Semicolon literally translates to “half colon.”

What are some words that use the combining form semi-?

• semiannual
• semiautomatic
• semicircle
• semifinal
• semiliterate
• semiprivate

What are some other forms that semi– may be commonly confused with?

• semei-
• septi-

Break it down!

The word literate means “able to read and write.” With this in mind, what does semiliterate mean?