aluminum

noun

alu·​mi·​num ə-ˈlü-mə-nəm 

: a silver-white metallic chemical element with atomic number 13 that has good electrical and thermal conductivity, high reflectivity, and resistance to oxidation

—often used before another noun

aluminum foil

The sweet spot, the point in a bat where vibration supposedly is least, is said to be two times larger on an aluminum bat than on a wood one.

—Hank Hersch

Before he evacuated, Mr. Gonzales tied the boat down with four gigantic ropes and all the storm could do was knock it off the construction blocks. He slowly climbs a battered aluminum ladder propped up on the port side.

—Ken Wells

see Chemical Elements Table

Examples of aluminum in a Sentence

Recent Examples on the Web

No country-specific exemptions have so far been announced for the new tariffs on steel and aluminum, which are set to come into effect on March 12. —Justin Gest, Newsweek, 11 Feb. 2025

President Donald Trump’s steel and aluminum duties could boost shares of Steel Dynamics , according to KeyBanc. —Lisa Kailai Han, CNBC, 11 Feb. 2025

Related article Americans could pay a high price for Trump’s reciprocal tariffs On Monday, Trump imposed a 25% tariff on all steel and aluminum imports into the United States with no exceptions or exemptions. —Bryan Mena, CNN, 11 Feb. 2025

Powell’s appearance comes with inflation still above the Fed’s 2% target and the Trump administration upending many longtime U.S. policies by imposing tariffs on steel and aluminum and seeking to cut government spending drastically. —Christopher Rugaber, Los Angeles Times, 11 Feb. 2025

Word History

Etymology

alumine "alumina" (borrowed from French, borrowed from Latin alūmin-, alūmen alum entry 1) + -um (in the names of other metals, as platinum entry 1, tantalum)

First Known Use

1812, in the meaning defined above

Phrases Containing aluminum

• aluminum foil
• aluminum oxide
• aluminum sulfate

Kids Definition

aluminum

noun

alu·​mi·​num ə-ˈlü-mə-nəm 

: a silver-white malleable light element that conducts electricity and heat well, is highly resistant to oxidation, and is the most abundant metal in the earth's crust see element

Medical Definition

aluminum

noun

alu·​mi·​num ə-ˈlü-mə-nəm 

: a silver-white malleable ductile light trivalent metallic chemical element with atomic number 13 that has good electrical and thermal conductivity, high reflectivity, and resistance to oxidation

—symbol Al see Chemical Elements Table