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

The creature, Clements and his team determined, is actually a relative of the nautilus — a cephalopod with both tentacles and a shell. —Samantha Agate, Miami Herald, 23 Apr. 2026

New research has reclassified the specimen as a relative of the nautilus, a cephalopod with both tentacles and a shell. —Samantha Agate, Fort Worth Star-Telegram, 23 Apr. 2026

The fossil was identified as the world's oldest octopus in 2000 — but is now considered the oldest soft-tissue nautilus in the world. —Andrea Margolis, FOXNews.com, 13 Apr. 2026

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

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