metalloid

adj. of metalloid (element which is both metallic and non-metallic); resembling both a metal and a nonmetal

n. element which is both metallic and nonmetallic; nonmetal

Metalloid is a term used in chemistry when classifying the chemical elements. On the basis of their general physical and chemical properties, nearly every element in the periodic table can be termed either a metal or a nonmetal - however a few elements with intermediate properties are referred to as metalloids. (In Greek metallon = metal and eidos = sort)
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Adjective
1. of or being a nonmetallic element that has some of the properties of metal; "arsenic is a metalloid element"
(similar) nonmetallic, nonmetal

n. metalloid, nonmetal, chemical element without metallic properties

adj. metalloid, of metalloid; resembling both a metal and a nonmetal

(n.)
Now, one of several elementary substances which in the free state are unlike metals, and whose compounds possess or produce acid, rather than basic, properties; a nonmetal; as, boron, carbon, phosphorus, nitrogen, oxygen, sulphur, chlorine, bromine, etc., are metalloids.
  

(n.)
Formerly, the metallic base of a fixed alkali, or alkaline earth; -- applied by Sir H. Davy to sodium, potassium, and some other metallic substances whose metallic character was supposed to be not well defined.
  

(a.)
Having the properties of a nonmetal; nonmetallic; acid; negative.
  

(a.)
Having the appearance of a metal.