The plural of alumnus is alumni.
A graduate or former student of a school, college, or university. The word alumnus is typically used for a male graduate.
The word alumni was originally intended for multiple male graduates yet the modern day usage of the word can often refer to a single graduate or group of graduates of either male or mixed gender.
For female graduates in the singular or plural see 'alumna or alumnae?'.
The word alumnus is of Latin origin and its first known use dates back to 1645.
Being a Latin word, the plural of alumnus is alumni.
This follows the standard rules for pluralizing Latin words by replacing the suffix -us with -i.
Singular Example: One has to study hard to become an alumnus of this college.
Plural Example: The alumni gathered together to take photos and throw their caps in the air as was tradition at the graduation ceremoney.
According to Statista.com around 37.9% of Americans over 25 are alumni of college level or higher. This is compared to only 7.7% in 1960.