the power or faculty of seeing; perception of objects by use of the eyes; vision.

an act, fact, or instance of seeing.

one's range of vision on some specific occasion

Land is in sight.

a view; glimpse.

mental perception or regard; judgment.

something seen or worth seeing; spectacle

the sights of London.

Informal . something unusual, surprising, shocking, or distressing

They were a sight after the fight.

Commerce .

presentation of a bill of exchange

a draft payable at two months after sight.

a showing of goods, esp. gems, held periodically for wholesalers.

Older Use . a multitude; great deal

It's a sight better to work than to starve.

an observation taken with a surveying, navigating, or other instrument to ascertain an exact position or direction.

any of various mechanical or optical viewing devices, as on a firearm or surveying instrument, for aiding the eye in aiming.

Obsolete . skill; insight.

to see, glimpse, notice, or observe

to sight a ship to the north.

to take a sight or observation of (a stake, coastline, etc.), esp. with surveying or navigating instruments.

to direct or aim by a sight or sights, as a firearm.

to provide with sights or adjust the sights of, as a gun.

to aim or observe through a sight.

to look carefully in a certain direction. ?

at first sight

at the first glimpse; at once

It was love at first sight.

at sight

immediately upon seeing, esp. without referring elsewhere for assurance, further information, etc.

to translate something at sight.

Commerce . on presentation

a draft payable at sight.

catch sight of

to get a glimpse of; espy

We caught sight of the lake below.

know by sight

to recognize (a person or thing) seen previously

I know him by sight, but I know nothing about him.

not by a long sight

Informal . definitely not

Is that all? Not by a long sight.

on or upon sight

immediately upon seeing

to shoot him on sight; to recognize someone on sight.

out of sight

beyond one's range of vision.

Informal . beyond reason; exceedingly high

The price is out of sight.

Slang . (often used interjectionally) fantastic; marvelous

a ceremony so glamorous it was out of sight.

sight for sore eyes

someone or something whose appearance on the scene is cause for relief or gladness.

sight unseen

without previous examination

to buy something sight unseen.