nautilus

noun

nau·​ti·​lus ˈnȯ-tə-ləs 

ˈnä-

plural nautiluses or nautili ˈnȯ-tə-ˌlī 

-ˌlē,

ˈnä-

1

: any of a genus (Nautilus) of cephalopod mollusks of the South Pacific and Indian oceans with a spiral chambered shell that is pearly on the inside

called also chambered nautilus

2

: paper nautilus

Illustration of nautilus

• nautilus 1

Examples of nautilus in a Sentence

Recent Examples on the Web

But later research showed that decay processes can give a similar appearance in the eyes of cephalopods, like squid or nautiluses. —Cody Cottier, Discover Magazine, 8 July 2025

The hard shell of the nautilus encloses a series of chambers. —Amanda Kooser, Forbes, 6 Dec. 2024

Clutching her custom Alaïa crystal mesh dress across her chest like Botticelli's Venus emerging from the shell, the nautilus of the Frank Lloyd Wright interior rising above her, the mononym icon appeared like a siren fresh from a shimmering sea. —Chloe Malle, Vogue, 7 Sep. 2024

The state of cephalopod science has prompted the United States National Institutes of Health to consider whether these animals—which also include squid, cuttlefish, and nautiluses—deserve the same research protections as vertebrates. —Emily Mullin, WIRED, 6 Oct. 2023

Word History

Etymology

New Latin, from Latin, paper nautilus, from Greek nautilos, literally, sailor, from naus ship

First Known Use

1601, in the meaning defined at sense 1

Phrases Containing nautilus

• chambered nautilus
• paper nautilus
• pearly nautilus

Kids Definition

nautilus

noun

nau·​ti·​lus ˈnȯt-ᵊl-əs 

ˈnät-

plural nautiluses or nautili -ᵊl-ˌī 

-ˌē

1

: any of a genus of mollusks of the South Pacific and Indian oceans that are cephalopods and have a spiral chambered shell that is pearly on the inside

called also chambered nautilus

2

: paper nautilus