Ada and Mike meant a lot to Eve (4)
I believe the answer is:
adam
'meant a lot to eve' is the definition.
I can't tell whether this definition defines the answer.
'ada and mike' is the wordplay.
'and' means one lot of letters go next to another.
'mike' becomes 'M' (phonetic alphabet: alpha, bravo, charlie etc.).
'ada'+'m'='ADAM'
Can you help me to learn more?
(Other definitions for adam that I've seen before include "First Christian ancestor" , "One of our common ancestors?" , "Biblical progenitor of human race" , "First man in the Bible" , "one might confuse with total stranger" .)