Where most people live (4)
(Other definitions for eurasia that I've seen before include "Turkey, and so on" , "Large landmass combining two continents" , "Combined continent" , "Two continents considered as one" , "Two continents, considered as a whole" .)
'where most people live' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for asia that I've seen before include "Tigers found here" , "Great continent" , "The nations of the East, collectively" , "Continent of the Hindu Kush" , "Populous continent" .)