There is no standard abbreviation. I am sure you have already done a Google search and found no consistently used abbreviation. There are some commonly used rules that could be applied to 'classification':
Put a period after the first syllable:
Class.
Words ending in 'tion' are often abbreviated using apostrophe-n:
Class'n
Sometimes an extra consonant is included:
Classf'n
A Google search shows all of these in use. The best may depend on the context. For example the first suggestion above could be an abbreviation for a number of different words and may not be the best pick unless within a constrained context.
cls.
CsO
IN is the abbreviation for the state of Indiana.
misc.is the abbreviation for miscellaneous.
The abbreviation for Nebraska NE.Nebraska's abbreviation is NE.The postal abbreviation for Nebraska is NE. Another common abbreviation is Nebr..NENENENE
Ben Nevis has no abbreviation of its name.
The abbreviation for teaspoon is 'tsp'
The word class is not an abbreviation, its a word. You may see an abbreviation 'class.' using a period to indicate that it's an abbreviation. If it is used with the period, it's short for 'classification'.
There is none.
The abbreviation for Private First Class is PFC.
in class support...
Tourismo Internationale
mr.
There are many uses for the abbreviation PFC. The abbreviation most commonly stands for private first class, power factor correction, or perfluorocarbon.
The usual meaning of PE is "physical education, gym class."If you want to see many more meanings of this abbreviation, see: pe
I've used "conf" but and not certain this will be readily recognized.
The medical abbreviation "NYHA Class 2" refers to the New York Heart Association Functional Classification, which categorizes heart failure patients based on symptom severity. Class 2 indicates that the patient experiences mild symptoms with ordinary physical activity, such as fatigue or shortness of breath.
On property taxes, a Class CD abbreviation typically stands for multi asset. It means a combination of asset classes (such as cash, equity or bonds) used as an investment.
system international its the distance, time and mass. our class goes by centimeters, seconds, and grams