What is a poem called whose first letters of each line spell out a word?

What is a poem called whose first letters of each line spell out a word?

وہ نظم کسے کہتے ہیں جس کی ہر سطر کے پہلے حروف سے ایک لفظ نکلے؟
Explanation

An acrostic poem is a type of poetry where the first, last, or other letters in a line spell out a particular word or phrase. 

It comes from the Greek words "akros" and "stichos" 

Which are synonymous with word 'outermost' and 'line of verse'

Example:

Acrostic poem to describe the specific word 'SUN'.

Sun shines brightly

Up in the sky

Nice and warm on my face


Additional information 


EpicA long poem or film usually dealing with adventure 
HaikuA kind of Japanese poem with 17 syllables usually dealing with nature, weather, and seasons
AlliterativeA conspicuous repetition of identical sounds (mostly constant) in verse.