In another word 和 in other words 的区别

He does not feel good,( ),he is ill.
A.in other words
B.in another word
in other words是换句话说的意思,in another word 是另外一种说法的意思,从意思上看不出区别,但已经约定俗成了,如果表达的前面刚说的东西就用 in other words