Change in America, welcoming Republican and key symbol of Islam (8)
I believe the answer is:
crescent
'change in america' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.
'welcoming republican and key symbol of islam' is the wordplay.
'welcoming' is an insertion indicator (I've seen this in other clues).
'republican' becomes 'R' (abbreviation in US politics).
'and' means one lot of letters go next to another.
'key' becomes 'esc' ('Escape' key on a computer keyboard).
'symbol of islam' becomes 'cent' (I am not sure about this - if you are sure you should believe this answer much more).
'r'+'esc'='resc'
'resc' going into 'cent' is 'CRESCENT'.
Can you help me to learn more?
(Other definitions for crescent that I've seen before include "Sickle-shape" , "Shape of moon in first or last quarter" , "Muslim emblem" , "Young moon shape" , "Young-moon shape" .)