older is it =elder???

Older = 年歲大些的 (老過)
Elder = 在家庭內的大過

John is older than Mary. (John = 10歲 , Mary = 9歲)
John is elder than Peter. (John 在家庭內的大過 Peter)

Hope this helps!


2008-01-16 15:13:28 補充：
John 是[哥哥] Peter 是[弟弟]了

Older is different with elder.

Say you are at age 10 (say Peter), and your elder brother is at age 12 (say Tom). we can say:
e.g. 1) Tom is older than Peter. Tom is Peter's elder brother.

e.g. 2) That older woman is get more worse at the traffic accident.