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

On the cathode side, iron and iron chloride particles mix with sodium chloride (table salt), all immersed in molten sodium aluminum chloride (NaAlCl₄). —Tejasri Gururaj, Interesting Engineering, 6 Jan. 2026

Despite broad evidence that using such adjuvants are safe, Kennedy has argued that aluminum in vaccines is linked to allergies and other health problems. —Jen Christensen, CNN Money, 6 Jan. 2026

Classic Stainless Steel Non-Stick Chef's Pan Upgrade your kitchen gear with this 2-quart pan that delivers excellent heat distribution thanks to its aluminum core. —Michele Laufik, Martha Stewart, 5 Jan. 2026

Easy to erect, instant canopies—often used for camping or outdoor parties—have steel or aluminum frames and waterproof polyester covers. —Lee Wallender, The Spruce, 4 Jan. 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