observable

adjective

ob·​serv·​able əb-ˈzər-və-bəl 

1

: noteworthy

the trend is observable all over the country

2

: capable of being observed : discernible

the size of the observable universe

observability

əb-ˌzər-və-ˈbi-lə-tē 

noun

observable noun

observably

əb-ˈzər-və-blē 

adverb

Synonyms of observable

• visible
• visual
• noticeable

Examples of observable in a Sentence

the size of the observable universe

scientists often work with phenomena that are not directly observable

Recent Examples on the Web

The turtles’ unusually long lifespan of up to 70 or 80 years makes the process observable over a long period of time, says Stefanov, allowing the scientists to collect large amounts of data. —Lise Pedersen, Variety, 24 Apr. 2026

Neither liquid showed observable decay or fermentation. —Scott Lafee, San Diego Union-Tribune, 21 Apr. 2026

This story of star-formation is ubiquitous throughout our natural history, with sextillions of stars populating our observable Universe today, with nuclear fusion providing the sustaining energy for most modern stars. —Big Think, 20 Apr. 2026

As the average color of all the light from stars and galaxies in the observable universe, cosmic latte reflects the types of stars that are most common today. —Manjishtha Bhattacharyya, Encyclopedia Britannica, 13 Apr. 2026

Word History

Etymology

borrowed from Middle French & Latin; Middle French, "that must or can be observed," borrowed from Latin observābilis "capable of being observed," from observāre "to give attention to, watch carefully, observe" + -bilis "capable (of acting) or worthy of (being acted upon)" — more at -able

First Known Use

1589, in the meaning defined at sense 2

Rhymes for observable

• unobservable

Kids Definition

observable

adjective

ob·​serv·​able əb-ˈzər-və-bəl 

: able to be observed : noticeable

observably

-blē 

adverb