The most common and most likely answer to this crossword clue is the 6 letter word MINBAR
M
I
N
B
A
R
Buddy explains!
The straight part
We know that "Term for tub in front of mosque Iran constructed" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case term for tub in front of mosque iran constructed = minbar.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does MINBAR mean?
MINBAR noun- A pulpit in a mosque, usually shaped like a small tower, where the imam stands to deliver sermons.