ultrathin

adjective

ul·​tra·​thin ˌəl-trə-ˈthin 

: extremely or extraordinarily thin

ultrathin phones

ultrathin fashion models

The molecules ride on the surface like a film of soap and assemble themselves into an ultrathin layer about one-millionth of an inch thick.

—Mike May

Synonyms

• fine
• hairline
• narrow
• needlelike
• paper-thin
• skinny
• slender
• slim
• slim-jim
• thin

Examples of ultrathin in a Sentence

a new generation of flat-panel TVs that were ultrathin

Recent Examples on the Web

The ultrathin laptop is powered by an Intel Core Ultra 7 258V processor, with up to 32GB of RAM and up to 1TB of SSD storage. —Barry Collins, Forbes, 7 Jan. 2025

Yes, the brand’s stylish intimates look great on any Instagram grid, but these ultrathin thong panties will become your new favorite pair. —Malia Griggs, Glamour, 11 Dec. 2024

In full-grain leather and mesh upper, these boots are warm but ultrathin and flexible, with a waterproof membrane that keeps water out and lets moisture out. —Alesandra Dubin, Travel + Leisure, 8 Dec. 2024

These ultrathin hydrocolloid patches conceal whiteheads and blackheads while clarifying the skin. —Jenny Berg, Vogue, 14 Sep. 2024

Word History

First Known Use

1851, in the meaning defined above

Medical Definition

ultrathin

adjective

ul·​tra·​thin ˌəl-trə-ˈthin 

: exceedingly thin

ultrathin sections for use in electron microscopy