Sentence:  At two thirty he sent Fujimoto to the top of the <WSD>wall</WSD> at the northeast corner of the mission to keep an eye on the ridge road and give a signal when he first glimpsed the approach of Kayabashi 's party . 
Meaning of the word marked with <WSD> tags:  an architectural partition with a height and length greater than its thickness; used to divide or enclose an area or to support another structure