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

But just as these large gray disks reify the front-facing imagistic view of the planar surface, similarly sized aluminum disks in related sculptures such as Hardware Romance, 2021, are polished to an almost literal mirror surface. —Gordon Hughes, Artforum, 1 Mar. 2026

And then there are the national security tariffs under Section 232 of the Trade Expansion Act of 1962 on steel, aluminum, copper and other items. —Matt Egan, CNN Money, 1 Mar. 2026

Every roller runs on its own bearing, with custom aluminum hubs and TPU (thermoplastic polyurethane, a flexible 3D-printing material) tires. —Omar Kardoudi march 01, New Atlas, 1 Mar. 2026

Researchers avoided contaminating the samples with other plastics by substituting standard tools with those made of aluminum, cotton and other non-plastic material, the release noted. —Khloe Quill, FOXNews.com, 1 Mar. 2026

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

Rhymes for aluminum

• aluminium

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