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

That evaluation must be documented — not assumed — and tied to observable conditions rather than age alone. —Mike McGilvary, Sun Sentinel, 15 Feb. 2026

Pointer states correspond to properties that are classically observable, such as position or charge. —Quanta Magazine, 13 Feb. 2026

Naval analysts note that snorkeling periods can expose submarines to detection because the intake mast and exhaust emissions create observable signatures. —Kaif Shaikh, Interesting Engineering, 9 Feb. 2026

Most of the galaxies in the Universe are small and faint; most of the stars in the Universe emit primarily red or even infrared light; most of the galaxies in the Universe are rich in dust; most of the Universe that’s observable to us are located at significant cosmic distances. —Big Think, 4 Feb. 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