Fwd: different between index and key when create table

[Vivian Wang]

mysql:
Can anyone tell me what is different between index and key when creating 
table?
like this situation:

create table info ( fname char(9), lname char (15), address char(30), 
index(lname));
or
create table info ( fname char(9), lname char(15), address char(30), 
key(lname));

Thanks.