1, The full form of K is Kelvin. It’s used on Academic & Science ,Units in Worldwide

Kelvin (K) is a unit of measure for temperature based upon an absolute scale. It is named after the British physicist and engineer William Thomson, also called Lord Kelvin.

2, The full form of K is Potassium. It’s used on Academic & Science ,Chemistry in Worldwide

Potassium (symbol: K) is a chemical element with atomic number 19. The name is derived from the English word “potash”. The K symbol for potassium comes from the Latin name for potash, kalium.

3, The full form of K is Karat. It’s used on Academic & Science ,Units in Worldwide

Karat (kt or K), sometimes also spelled as carat, is a measure of purity for gold alloys. Karat is the percentage of Gold in a piece of metal expressed in fraction of 24th’s. For example, 22 karat means 22/24, Gold = 91.7%

24 karat gold is the purest gold.

Note:

karat not to be confused carat (ct), a unit of mass equal to 200 mg.

4, The full form of K is Cathode. It’s used on Academic & Science ,Electronics in Worldwide

K is sometimes used in diodes and transistors to denote Cathode. The name cathode is derived from the Greek word κάθοδος (kathodos), meaning descending or going down.

5, The full form of K is Kindergarten. It’s used on Academic & Science ,Daycare & Preschool in Worldwide

Kindergarten (K) is a nursery school or a preschool for children age 4 to 6, to prepare them for primary school. The word kindergarten is from German [ˈkɪndɐˌɡaːɐ̯tn̩] , literally means children’s garden.

6, The full form of K is Kellogg Company. It’s used on Business ,NYSE Symbols in United States

Kellogg Company (NYSE symbol: K) is a multinational food manufacturing company headquartered in Battle Creek, Michigan, United States.

7, The full form of K is Okay

Okay and OK are two acceptable spellings of the same word. There’s no difference between OK and okay. The older term, OK, (possibly) derived from an abbreviation for an intentional misspelling of “all correct.” The terms are both standard English. For extremely formal writing, always consult the relevant style guide.