TransDiv is the authorized abbreviation or acronym used by the

U.S. Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage of ...

during

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

for "transport division." The commander of a transport division was known as ''ComTransDiv'' (followed by the number of the division).

References

OPNAV 29-P1000
Seagoing divisions of the United States Navy {{US-navy-stub