metalloid

American  

[met-l-oid] / ˈmɛt lˌɔɪd /

noun

1. a nonmetal that in combination with a metal forms an alloy.

2. an element that has both metallic and nonmetallic properties, as arsenic, silicon, or boron.

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adjective

1. of or relating to a metalloid.

2. resembling both a metal and a nonmetal.

metalloid British  

/ ˈmɛtəˌlɔɪd /

noun

1. a nonmetallic element, such as arsenic or silicon, that has some of the properties of a metal

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adjective

1. of or being a metalloid

2. resembling a metal

metalloid Scientific  

/ mĕt′l-oid′ /

1. An element that is not a metal but that has some properties of metals. Arsenic, for example, is a metalloid that has the visual appearance of a metal, but is a poor conductor of electricity; metalloids are generally semiconductors. The elements classified as metalloids are boron, silicon, germanium, arsenic, antimony, tellurium, and polonium. Metalloids can be viewed as a diagonal section on the Period Table, separating metals from nonmetals.

2. A nonmetallic element, such as carbon, that can form alloys with metals.

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Etymology

Origin of metalloid

First recorded in 1825–35; metall- + -oid

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Explanation

In chemistry, an element that isn't metal, but has many things in common with metal, is known as a metalloid. Silicon and arsenic are examples of metalloids. As far as scientific terms go, metalloid is not very precise. It's a general category for elements whose properties put them somewhere in between a metal and a nonmetal — they share characteristics of both. Scientists disagree over both the definition of metalloid and which elements can be described this way, though there are six on which most chemists concur: boron, silicon, germanium, arsenic, antimony, and tellurium.

Example Sentences

See Examples For:

metalloid

The charity Earthwatch Europe says trained citizen scientists have found potentially harmful levels of metal or metalloid at 52 freshwater sites across Corby.

From BBC ● Oct. 22, 2026

It said at every freshwater site, at least one metal or metalloid was present, at concentrations exceeding the level where "no adverse ecological effects are expected".

From BBC ● Oct. 18, 2026

Arsenic, a highly toxic element that resembles a metal but which is technically a metalloid, was an easily accessible poison in the mid-19th century; its poisonous properties were widely known.

From Salon ● Mar. 5, 2023

Note the background color denotes whether an element is a metal, metalloid, or nonmetal, whereas the element symbol color indicates whether it is a solid, liquid, or gas.

From Textbooks ● Feb. 14, 2019

This I afterwards ascertained beyond doubt to be a metalloid alloy whereof the principal ingredient was aluminium, or some substance so closely resembling it as not to be distinguishable from it by simple chemical tests.

From Across the Zodiac by Percy Greg

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