sea

noun

ˈsē 

1

a

: a great body of salt water that covers much of the earth

broadly : the waters of the earth as distinguished from the land and air

b

: a body of salt water of second rank more or less landlocked

the Mediterranean sea

c

: ocean

d

: an inland body of water

—used especially for names of such bodies

the Caspian Sea

2

a

: surface motion on a large body of water or its direction

also : a large swell or wave

—often used in plural

heavy seas

b

: the disturbance of the ocean or other body of water due to the wind

3

: something likened to the sea especially in vastness

a sea of faces

4

: the seafaring life

5

: mare entry 2

sea adjective

Phrases

at sea

1

: on the sea

specifically : on a sea voyage

2

: lost, bewildered

to sea

: to or on the open waters of the sea

Synonyms

• ocean
• waters

Examples of sea in a Sentence

the seas of the Southern Hemisphere

millions of plants and animals live in the sea

Recent Examples on the Web

The successful trial marks the first time a naval variant of the IRIS-T family missile has been launched at sea, paving the way for serial introduction across the fleet. —Aamir Khollam, Interesting Engineering, 17 Oct. 2025

Some stars collapsed to the sea floor, dissolved into piles of goo. —JSTOR Daily, 17 Oct. 2025

Some firms have scurried to ship early, but even a few days’ delay at sea could blow up their margins. —Veronique De Rugy, Oc Register, 17 Oct. 2025

Every night after dusk, one of the world’s largest migrations begins, as deep sea creatures rise to the surface to feed. —New York Times, 16 Oct. 2025

Word History

Etymology

Middle English see, from Old English sǣ; akin to Old High German sē sea, Goth saiws

First Known Use

before the 12th century, in the meaning defined at sense 1a

Phrases Containing sea

• beam sea
• between the devil and the deep blue sea
• by sea
• California sea lion
• Chilean sea bass
• deep-sea
• fish in the sea
• go to sea
• high sea
• many/plenty more fish in the sea
• not the only fish in the sea
• out to sea
• put (out) to sea
• sea air
• sea anchor
• sea anemone
• sea bass
• sea bed
• sea biscuit
• sea bream
• sea breeze
• sea captain
• sea change
• sea chest
• sea cow
• sea crayfish
• sea cucumber
• sea devil
• sea dog
• sea duck
• sea duty
• sea eagle
• sea fan
• sea fire
• sea floor
• sea grape
• sea green
• sea hare
• sea holly
• sea island cotton
• sea kale
• sea king
• sea lamprey
• sea-lane
• sea lavender
• sea lawyer
• sea legs
• sea lettuce
• sea level
• sea lily
• sea lion
• sea-maid
• sea-maiden
• sea mew
• sea mile
• sea monkey
• sea monster
• sea mouse
• sea nettle
• sea oats
• sea onion
• sea otter
• sea pen
• sea pink
• sea power
• sea puss
• sea robin
• sea room
• sea rover
• sea-run
• sea salt
• sea scallop
• sea scorpion
• sea serpent
• sea slug
• sea snake
• sea spider
• sea squirt
• sea star
• sea stores
• sea trout
• sea turtle
• sea urchin
• sea wasp
• sea whip
• sea wrack
• spotted sea trout
• Steller's sea cow
• sub-sea
• swept out to sea
• the open sea
• wash out to sea
• white sea bass

Rhymes for sea

• be
• bee
• bree
• cree
• fee
• flea
• flee
• free
• gee
• ghee
• glee
• he

Kids Definition

sea

noun

ˈsē 

1

a

: a great body of salty water that covers much of the earth

also : the waters of the earth

b

: a body of salt water not as large as an ocean

the Mediterranean Sea

c

: ocean sense 1

d

: an inland body of water either salt or fresh

the Sea of Galilee

2

: rough water

a high sea swept the deck

3

: something suggesting the sea (as in great size or depth)

a golden sea of wheat

4

: a life involving marine travel

hoped to make a career of the sea

5

: mare entry 2

sea adjective