Main Difference
The main difference between Sky and Ski is that the Sky is a everything that is above the surface of the Earth and Ski is a narrow strip of wood, plastic, metal for skiing.
Sky
The sky (or celestial dome) is everything that lies above the surface of the Earth, including the atmosphere and outer space.
In the field of astronomy, the sky is also called the celestial sphere. This is viewed from Earth’s surface as an abstract dome on which the Sun, stars, planets, and Moon appear to be traveling. The celestial sphere is conventionally divided into designated areas called constellations. Usually, the term sky is used informally as the point of view from the Earth’s surface; however, the meaning and usage can vary. In some cases, such as in discussing the weather, the sky refers to only the lower, more dense portions of the atmosphere.
During daylight, the sky appears to be blue because air scatters more blue sunlight than red. At night, the sky appears to be a mostly dark surface or region spangled with stars. During the day, the Sun can be seen in the sky unless obscured by clouds. In the night sky (and to some extent during the day) the Moon, planets and stars are visible in the sky. Some of the natural phenomena seen in the sky are clouds, rainbows, and aurorae. Lightning and precipitation can also be seen in the sky during storms. Birds, insects, aircraft, and kites are often considered to fly in the sky. Due to human activities, smog during the day and light pollution during the night are often seen above large cities.
Ski
A ski is a narrow strip of semi-rigid material worn underfoot to glide over snow. Substantially longer than wide and characteristically employed in pairs, skis are attached to ski boots with ski bindings, with either a free, lockable, or partially secured heel. For climbing slopes, ski skins (originally made of seal fur, but now made of synthetic materials) can be attached at the base of the ski.
Originally intended as an aid to travel over snow, they are now mainly used recreationally in the sport of skiing.
Sky (noun)
The atmosphere above a given point, especially as visible from the ground during the day.
“That year, a meteor fell from the sky.”
Sky (noun)
The part of the sky which can be seen from a specific place or at a specific time; its condition, climate etc.
“I lay back under a warm Texas sky.”
“We’re not sure how long the cloudy skies will last.”
Sky (noun)
Heaven.
“This mortal has incurred the wrath of the skies.”
Sky (noun)
ellipsis of sky blue
Sky (noun)
In an art gallery, the upper rows of pictures that cannot easily be seen.
Sky (noun)
A cloud.
Sky (verb)
To hit, kick or throw (a ball) extremely high.
Sky (verb)
To hang (a picture on exhibition) near the top of a wall, where it cannot be well seen.
Sky (verb)
To drink something from a container without one’s lips touching the container.
Ski (noun)
one of a pair of long flat runners designed for gliding over snow
Ski (noun)
one of a pair of long flat runners designed for gliding over water while pulled by a boat
Ski (noun)
one of a pair of long flat runners under some flying machines, used for landing
Ski (verb)
to move on skis
Ski (verb)
to travel over (a slope etc.) on skis; to travel on skis at (a place), especially as a sport
Ski (noun)
each of a pair of long, narrow pieces of hard, flexible material, typically pointed and turned up at the front, fastened under the feet for travelling over snow
“a pair of skis”
“neither of them had ever been on skis before”
Ski (noun)
a ski-like device fitted to the underside of a vehicle or aircraft to enable it to travel or land on snow or ice.
Ski (noun)
relating to or used for skiing
“ski boots”
“a ski instructor”
Ski (noun)
another term for waterski
Ski (verb)
travel over snow on skis; take part in the sport or recreation of skiing
“they skied down the mountain”
Ski (verb)
ski on (a particular ski run or type of snow)
“off-piste spring snow is easy to ski”